You just started a new job in Japan. Your HR manager slides a form across the desk and says: マイナンバーを記入してください. You hand over a paper document that arrived in the mail when you first registered at the city office. Your manager shakes their head: それは個人番号通知書ですね。マイナンバーカードはありますか? Four different words are now floating in the air — and they all seem to be about the same thing. What is actually going on?
Japan's individual number system uses four distinct terms that English speakers frequently collapse into one vague phrase. Get them mixed up and your paperwork gets returned, your bank account application stalls, or your employer's payroll team loses a whole afternoon. This article breaks down each word precisely, explains when and where each one appears in real life, and gives you a clear decision rule so you always reach for the right term.
And yes — if you are a foreign resident with a 住民票（じゅうみんひょう）registered at your local city office, this applies to you too. Foreign residents in Japan with a residence record receive a マイナンバー just like Japanese citizens do.
| Japanese | Reading | What it is | Key point |
|---|---|---|---|
| マイナンバー | まいなんばー | The 12-digit individual number (common name) | The number itself; used in everyday speech |
| 個人番号 | こじんばんごう | The 12-digit individual number (official/legal name) | The same number; appears on official forms and laws |
| マイナンバーカード | まいなんばーかーど | Physical IC card with photo | Functions as both photo ID and number proof |
| 個人番号通知書 | こじんばんごうつうちしょ | Paper notification document | Tells you your number only; cannot be used as ID or number proof in most contexts |
Quick Answer: マイナンバー vs 個人番号 vs マイナンバーカード vs 個人番号通知書
マイナンバー — the everyday name for the number
マイナンバー（まいなんばー）is the popular, government-branded name for Japan's 12-digit individual number. The name is a katakana blend of the English words “my” and “number,” introduced when the system launched in 2015. You will hear and read this term in news reports, on posters at the city office, in HR emails, and on bank account application screens. It is the word that most people use in everyday speech and writing.
個人番号 — the official legal term for the same number
個人番号（こじんばんごう）means “individual number” and is the legally precise term used in statutes, regulations, and official documents. It refers to exactly the same 12-digit number as マイナンバー. When you fill out a tax form or a social insurance document, the field will almost always say 個人番号 rather than マイナンバー, because the law uses that formal term. Think of it as the difference between saying “car” in conversation and writing “motor vehicle” in a legal contract.
マイナンバーカード — the physical IC card with your photo
マイナンバーカード（まいなんばーかーど）is the physical card — roughly the size of a credit card — that the government issues to anyone who applies for one. It has your photo printed on the front, your name, address, date of birth, sex, and your 12-digit number. It is an IC (integrated circuit) chip card with two embedded digital certificates used for electronic procedures. Crucially, the マイナンバーカード serves a dual function: it proves who you are (like a driver's licence) and it proves what your number is, both at the same time.
個人番号通知書 — the paper document that just tells you the number
個人番号通知書（こじんばんごうつうちしょ）is a paper document issued by the government to notify you of your 12-digit number. It is not a card. It has no photo. It cannot be used to verify your identity, and in most official contexts it cannot even be used to prove your number. It is purely informational — the government's way of saying: here is your number, please keep this somewhere safe. Many people confuse it with the マイナンバーカード or with the older 通知カード（つうちカード）, which has different rules.
What Does マイナンバー Mean?
マイナンバー as the common name for the 12-digit individual number
Japan's individual number system assigns every person registered in the Japanese population register a unique 12-digit number. This number does not change over your lifetime (except in rare circumstances such as a privacy breach). The government chose the brand name マイナンバー to make the system sound accessible and personal — “my number” — but underneath the branding, the same system is called the 社会保障・税番号制度（しゃかいほしょう・ぜいばんごうせいど：Social Security and Tax Number System）in official law.
The number itself is 12 digits. Japan's corporate equivalent, 法人番号（ほうじんばんごう：corporate number）, is 13 digits, but that is a different system used for businesses rather than individuals.
Where is マイナンバー used?
マイナンバー appears in a wide range of administrative contexts. Here are the most common ones you will encounter as a learner or foreign resident:
| Context | Japanese phrase you see | When it happens |
|---|---|---|
| Starting a new job | マイナンバーを提出してください | HR collects your number for tax / social insurance registration |
| Year-end tax adjustment | 年末調整のマイナンバー確認 | Your employer verifies your number each year in November–December |
| Social insurance enrollment | 社会保険の手続きにマイナンバーが必要です | When joining health insurance, pension, or unemployment insurance |
| Opening a bank account | マイナンバーのご提出をお願いします | Banks are required to collect the number under anti-money-laundering rules |
| Tax filing (確定申告) | 確定申告書に個人番号を記入する | Note: the form itself says 個人番号 (see next section) |
| City hall procedures | 各種申請にマイナンバーが必要な場合があります | Childcare subsidies, welfare applications, residence notifications |
外国人も対象 — foreign residents also receive a マイナンバー
One of the most important things for foreign residents to know: if you have registered your address at a Japanese city or ward office and have a 住民票（じゅうみんひょう：residence record）, you will be issued a マイナンバー. This includes holders of work visas, student visas, dependent visas, permanent resident status, and others with a valid stay of three months or more. Short-term visitors on tourist visas are not included.
When you first register your address (転入届・てんにゅうとどけ), the system automatically generates a number for you. The 個人番号通知書 arrives at your registered address by post — typically within one to two weeks.
Yuka入社の手続きで、会社からマイナンバーの提出を求められました。（When completing my new employee paperwork, the company asked me to submit my My Number.）
Rei外国人でも住民票があればマイナンバーが付与されます。（Even foreign nationals receive a My Number if they have a residence record.）
Common example sentences
マイナンバーは12桁の番号です。
（My Number is a 12-digit number.）
マイナンバーは他人に教えないでください。
（Please do not tell your My Number to other people.）
銀行口座を開設する際にマイナンバーが必要になります。
（You will need your My Number when opening a bank account.）
What Does 個人番号 Mean?
個人番号 as the official legal term
個人番号（こじんばんごう）is the legally official term for the same 12-digit number. The word breaks down simply: 個人（こじん）means “individual / personal” and 番号（ばんごう）means “number.” While マイナンバー is a brand name created for public communication, 個人番号 is the term used in the 行政手続における特定の個人を識別するための番号の利用等に関する法律 — commonly called the マイナンバー法（まいなんばーほう：My Number Act）. The law says 個人番号; the poster at the station says マイナンバー.
個人番号を記入する — filling in the number on forms
Whenever you fill out an official government form, the field label will say 個人番号, not マイナンバー. This catches many learners off guard. Common forms where you will see the 個人番号 field include:
- 確定申告書（かくていしんこくしょ）— tax return form
- 給与所得者の扶養控除等（異動）申告書 — the annual tax withholding declaration given to your employer
- 健康保険・厚生年金保険 被保険者資格取得届 — enrollment form for health insurance and welfare pension
- 雇用保険 資格取得届 — employment insurance enrollment form
- 住民票の写し（個人番号入り）の申請書 — request form for a residence certificate that includes your number
個人番号確認書類 — documents that prove your number
The phrase 個人番号確認書類（こじんばんごうかくにんしょるい）means “documents used to confirm your individual number.” When a company or institution needs to verify both who you are and what your number is, they may ask for 番号確認書類 (a document showing the number) alongside 本人確認書類 (a document proving your identity). We will cover the distinction between these two types of documents in detail below.
住民票への記載 — the number on your residence certificate
When you request a copy of your 住民票（じゅうみんひょう：residence certificate）at the city office, you can choose whether to include your individual number on the document or not. The option is usually written as 個人番号を記載する／記載しない. Most administrative procedures that specifically require number verification will ask for the version with the number (個人番号あり).
書類上の表記 — why forms say 個人番号 not マイナンバー
If you search for マイナンバー on an official tax form, you will not find it. The National Tax Agency (国税庁・こくぜいちょう) uses 個人番号 exclusively on its forms because it is the legally defined term. Think of it the same way Americans might say “car” in conversation but a legal registration document says “motor vehicle.” The underlying reality is identical; the register is different.
Common example sentences
申告書の個人番号欄に12桁の番号を記入してください。
（Please write your 12-digit number in the individual number field on the declaration form.）
個人番号の提供を求める際は、本人確認も行う必要があります。
（When requesting the individual number, identity verification must also be conducted.）
個人番号を記載した住民票が必要な場合は、窓口でお申し出ください。
（If you need a residence certificate that includes your individual number, please let the counter staff know.）
What Does マイナンバーカード Mean?
マイナンバーカード as the physical IC card with photo
マイナンバーカード（まいなんばーかーど）is a plastic IC card approximately the size of a credit card, issued by the 地方公共団体情報システム機構（J-LIS: Japan Agency for Local Authority Information Systems）. Unlike the paper 個人番号通知書, the マイナンバーカード has:
- Your 顔写真（かおしゃしん：photo）on the front
- Your name, address, date of birth, and sex
- Your 12-digit individual number on the back
- An embedded IC chip containing two types of digital certificates (電子証明書）
The card is optional — you are not legally required to obtain one. However, as more procedures in Japan move online and as the card becomes the standard form of identity verification, not having one creates increasing friction in daily life.
顔写真付き本人確認書類 — a photo ID you can use anywhere
Because the マイナンバーカード has your photo, it qualifies as a 顔写真付き本人確認書類（かおしゃしんつきほんにんかくにんしょるい：photo-bearing identity document）. This means you can use it exactly like a driver's licence or passport at:
- Bank counters and online bank account applications
- Mobile phone carrier contracts
- Hotel check-ins
- Securities and investment account openings
- Age verification at convenience stores
- Any government window that requests 本人確認書類
個人番号の証明 — dual function as number proof
The マイナンバーカード is the only document that simultaneously satisfies both requirements most employers, banks, and government agencies need:
- 本人確認書類（ほんにんかくにんしょるい）— proves who you are (your identity)
- 番号確認書類（ばんごうかくにんしょるい）— proves what your number is
With any other combination of documents — say, your driver's licence plus your 通知カード — you are using two separate pieces of paper to satisfy two separate requirements. The マイナンバーカード does it alone. This is why HR managers and city hall staff often say: マイナンバーカードがあれば一枚で大丈夫です。 (“If you have the My Number Card, one document is enough.”)
コンビニ交付 — obtaining official documents at convenience stores
One of the most practical daily benefits of the マイナンバーカード is コンビニ交付（こんびにこうふ：convenience store certificate issuance）. By tapping your card on the multi-function printer at a Lawson, FamilyMart, or 7-Eleven (in participating municipalities), you can print official documents such as:
- 住民票の写し（じゅうみんひょうのうつし）— residence certificate
- 印鑑登録証明書（いんかんとうろくしょうめいしょ）— registered seal certificate
- 各種税証明書（かくしゅぜいしょうめいしょ）— tax certificates
- 戸籍謄本・戸籍抄本（こせきとうほん・こせきしょうほん）— family register certificates (in many municipalities)
コンビニ交付 is available 6:30 AM to 11:00 PM in most areas — far more convenient than city hall opening hours. You will need your 利用者証明用電子証明書 PIN (a four-digit number) to use this service.
マイナポータル — the government's online portal for procedures
マイナポータル（まいなぽーたる）is the government's online service portal (https://myna.go.jp/) that allows you to complete a growing range of administrative procedures from your smartphone or computer. Logging in requires your マイナンバーカード. Through マイナポータル you can:
- Submit change-of-address notifications (引越し手続き・ひっこしてつづき)
- Apply for childcare services
- Check your pension record
- File your income tax return (確定申告) via e-Tax integration
- View your vaccination history and health checkup records
電子証明書 — two digital certificates on the card
The IC chip contains two separate digital certificates, each with its own PIN:
| Certificate type | Japanese | PIN length | Used for |
|---|---|---|---|
| Signature certificate | 署名用電子証明書（しょめいようでんししょうめいしょ） | 6–16 alphanumeric characters | Filing tax returns, submitting official documents online (e-Tax, LoGo Form) |
| User authentication certificate | 利用者証明用電子証明書（りようしゃしょうめいようでんししょうめいしょ） | 4 digits | Logging in to マイナポータル, コンビニ交付, health insurance card use |
Both certificates expire every five years from issuance and must be renewed at the city office — even if the physical card itself is still valid. If you move to a new address, you must update both the card address and have the certificates renewed.
申請方法と受け取り — how to apply for the card
You can apply for a マイナンバーカード in the following ways:
- Online via the application website using the QR code printed on your 個人番号通知書
- By post using the application form that comes with the 個人番号通知書
- At a city office using a dedicated terminal
- At a convenience store (in some municipalities, using the Ki'osk terminal)
After applying, you wait approximately three to five weeks for a notification postcard (交付通知書・こうふつうちしょ) to arrive. You then visit the city office in person to receive the card and set your PINs. The card itself is free of charge（無料・むりょう）.
Common example sentences
マイナンバーカードは顔写真付きの本人確認書類として使えます。
（The My Number Card can be used as a photo-bearing identity document.）
マイナンバーカードがあれば、コンビニで住民票を取得できます。
（With the My Number Card, you can obtain a residence certificate at a convenience store.）
マイナポータルにログインするにはマイナンバーカードが必要です。
（You need the My Number Card to log in to マイナポータル.）
What Does 個人番号通知書 Mean?
個人番号通知書 as a notification document only
個人番号通知書（こじんばんごうつうちしょ）is a paper document — it looks like a letter or thin card in an envelope — that the government mails to your registered address. Its sole purpose is to inform you of your 12-digit number. The document includes your name, address, date of birth, and your individual number. It does not have a photo. It is not an IC card. It has no embedded chip.
The 個人番号通知書 replaced the older 通知カード（つうちカード）in May 2020. People who already had a 通知カード at that time can keep it, but no new 通知カード are issued. This distinction matters because the two documents have different rules about what they can be used for — more on that below.
本人確認書類として使えない — cannot be used as photo ID
This is the single most important point about the 個人番号通知書: it cannot be used as a 本人確認書類（ほんにんかくにんしょるい：identity verification document）. It has no photo, so it cannot verify that you are who you say you are. If a bank employee or HR staff member asks for 本人確認書類 and you hand over your 個人番号通知書, they will politely explain that they need something else — a driver's licence, passport, マイナンバーカード, or 在留カード.
番号確認書類としても使えない — cannot confirm your number in most contexts
This surprises many people: the 個人番号通知書 also cannot be used as a 番号確認書類（ばんごうかくにんしょるい：document confirming your number）in the standard two-document method. When an employer or government agency collects your individual number, they need to confirm both your identity and your number. The two-document combination most commonly accepted is: 本人確認書類 (e.g., driver's licence) + 番号確認書類 (e.g., 通知カード or number-inclusive 住民票). The 個人番号通知書 is not listed as a valid 番号確認書類 in most institutional guidelines.
通知カード との違い — the difference from the old notification card
Many people are confused because there are two different notification-style documents:
| 通知カード（old, pre-May 2020） | 個人番号通知書（new, post-May 2020） | |
|---|---|---|
| Format | Postcard-sized card | Paper document / letter |
| Still issued? | No (no longer newly issued) | Yes (for new registrations) |
| Photo? | No | No |
| Valid as 本人確認書類? | No | No |
| Valid as 番号確認書類? | Yes (if combined with separate 本人確認書類 and current address matches) | No (not accepted as 番号確認書類) |
| What to do with it | Keep it; it still works as a number-confirmation document in limited situations | Keep it for reference; apply for マイナンバーカード for actual use |
If you still have an old 通知カード and your name and address on it match your current registration, many institutions will still accept it as a 番号確認書類 when combined with a separate photo ID. However, if you have moved and not updated the address on your 通知カード, it may no longer be accepted.
紛失した場合 — what to do if you lose it
If you lose your 個人番号通知書, there is no formal reissuance process for it — it is simply an informational notice. Your individual number itself does not change. To confirm your number, you can:
- Request a 住民票の写し（個人番号入り）at the city office
- Apply for a マイナンバーカード, which will show your number on the back
- Consult your city or ward office directly
If you lose your マイナンバーカード, however, you must report it immediately to J-LIS at the dedicated 24-hour number (0120-95-0178 as of writing) to suspend the card, then visit your city office to request a replacement.
Common example sentences
個人番号通知書が届いたら、マイナンバーをメモして大切に保管してください。
（When your individual number notification document arrives, note down your My Number and keep it somewhere safe.）
個人番号通知書は本人確認書類にはなりません。
（The individual number notification document cannot be used as an identity verification document.）
通知カードをまだお持ちの方は、番号確認書類として使える場合があります。
（Those who still have a 通知カード may be able to use it as a number confirmation document in certain situations.）
マイナンバー vs 個人番号
Common name vs official legal term — the same 12-digit number
Let us make the most fundamental point completely clear: マイナンバーと個人番号は同じ番号です. There is one number. It has two names. マイナンバー is the brand name used in public communication; 個人番号 is the legal designation used in statutes and official forms. A person who has never heard the term 個人番号 but has memorized their マイナンバー already knows their 個人番号. They are identical.
会話ではマイナンバー — everyday speech
In conversation — whether you are talking to a colleague, a bank teller, or a city office clerk — マイナンバー is the natural and expected word. Signs say マイナンバー. TV commercials say マイナンバー. Your phone's news feed says マイナンバー. If you say 個人番号 in casual speech, the person you are talking to will understand you, but it sounds slightly stiff, as if you were reading from a statute.
書類では個人番号 — official forms and documents
Once you open an official form — a tax return, an insurance enrollment document, a formal application letter — the field label almost certainly says 個人番号. This is because the document is drafted in the register of the law, and the law calls it 個人番号. When you see 個人番号 on a form, write the same 12-digit number you know as your マイナンバー.
| マイナンバー | 個人番号 | |
|---|---|---|
| Register | Everyday / public communication | Legal / official documents |
| The number itself | Same 12-digit number | Same 12-digit number |
| Where you see it | Posters, news, HR emails, bank apps | Tax forms, insurance enrollment docs, government application forms |
| Legal basis | Brand name | Defined in the My Number Act (マイナンバー法) |
| Example usage | マイナンバーを提出してください | 個人番号を記入してください |
Tax and employment form examples
Form says: 個人番号（12桁）
What to write: Your マイナンバー (the same number)
HR email says: マイナンバーをご提出ください
What to submit: Your 個人番号 (the same number), verified through appropriate documents
Common mistakes with these two terms
The most common mistake is thinking they refer to different numbers. They do not. A second mistake is writing マイナンバー in the 個人番号 field of a form — write the digits themselves, not the word. A third mistake is refusing to fill in the 個人番号 field on a tax return because “I don't know my 個人番号.” If you know your マイナンバー, you know your 個人番号.
マイナンバーカード vs 個人番号通知書
Physical IC card vs paper notification document
This is where the most consequential confusion happens in real life — and where showing the wrong document causes the most practical problems. The マイナンバーカード and the 個人番号通知書 are fundamentally different objects serving different purposes.
| マイナンバーカード | 個人番号通知書 | |
|---|---|---|
| Format | Plastic IC card (credit card size) | Paper document (mailed in envelope) |
| Has photo? | Yes | No |
| Has IC chip? | Yes (with digital certificates) | No |
| Shows number? | Yes (on the back) | Yes (printed on document) |
| Valid as 本人確認書類? | Yes — accepted everywhere | No |
| Valid as 番号確認書類? | Yes — alone satisfies both | No (not accepted) |
| Usable for コンビニ交付? | Yes | No |
| Usable for マイナポータル? | Yes | No |
| Expiry | Card: 10 years (adults); certificates: 5 years | No expiry (informational only) |
| Needs to be obtained? | Must apply separately | Automatically mailed after registration |
Yukaマイナンバーカードは1枚で本人確認も番号確認もできます。（The My Number Card lets you confirm both your identity and your number with a single document.）
Rei個人番号通知書は番号を確認するためのお知らせなので、身分証明には使えません。（The 個人番号通知書 is a notice to inform you of your number, so it cannot be used as ID.）
本人確認書類 vs 番号確認書類
本人確認書類 — who you are
本人確認書類（ほんにんかくにんしょるい）are documents that verify your identity: your face, name, address, and legal existence. They must have a photo to qualify as the strongest type. Common 本人確認書類 include:
- マイナンバーカード — strongest option; has photo, chip, and satisfies all checks
- 運転免許証（うんてんめんきょしょう）— driver's licence; most widely held photo ID in Japan
- パスポート — passport; universally accepted but does not show a Japanese address
- 在留カード（ざいりゅうカード）— residence card; required document for non-Japanese residents
- 健康保険証（けんこうほけんしょう）— health insurance card; still accepted in some contexts but being phased out for higher-security uses
番号確認書類 — what your number is
番号確認書類（ばんごうかくにんしょるい）are documents that prove your 12-digit individual number. They exist because displaying your number in a database or form requires confirmation that the number genuinely belongs to you. Accepted 番号確認書類 include:
- マイナンバーカード — again, the strongest option; proves both identity and number alone
- 通知カード（つうちカード）— the old-format notification card (still valid in limited situations if the name and address match)
- 住民票の写し（個人番号入り） — residence certificate that includes the number
- 住民票記載事項証明書（個人番号入り） — certificate of items recorded in the residence register, including the number
Note: the 個人番号通知書 is not on this list. It was intentionally excluded from the accepted 番号確認書類 when the new format was introduced.
マイナンバーカード alone satisfies both requirements simultaneously
This is the practical heart of the entire article. When an employer, bank, or government agency collects someone's individual number, the マイナンバー法 and related guidelines require that the collecting party confirm two things at the same time:
- Verify the person's identity (本人確認)
- Confirm the number belongs to that person (番号確認)
Without a マイナンバーカード, you typically need two separate documents: one for identity and one for the number. With a マイナンバーカード, one document covers both. This is its defining advantage over every other document combination.
| Document(s) | Satisfies 本人確認? | Satisfies 番号確認? | Documents needed |
|---|---|---|---|
| マイナンバーカード alone | Yes | Yes | 1 |
| Driver's licence + 通知カード | Yes (licence) | Yes (通知カード, if address current) | 2 |
| Driver's licence + number-inclusive 住民票 | Yes (licence) | Yes (住民票) | 2 |
| 個人番号通知書 + driver's licence | Yes (licence) | No (通知書 not accepted) | Incomplete |
| 個人番号通知書 alone | No | No | Incomplete |
電子証明書 — digital certificates on the マイナンバーカード
The IC chip in the マイナンバーカード contains two digital certificates that enable electronic identity verification:
- 署名用電子証明書（しょめいようでんししょうめいしょ：Signature Digital Certificate）— used for creating legally valid electronic signatures when submitting official documents online (e-Tax, government e-forms). Requires a 6–16 character alphanumeric PIN. Expires every 5 years.
- 利用者証明用電子証明書（りようしゃしょうめいようでんししょうめいしょ：User Authentication Certificate）— used for logging into マイナポータル, コンビニ交付, and systems that use the card as a login token. Requires a 4-digit PIN. Also expires every 5 years.
暗証番号 — PIN codes for the card
When you receive your マイナンバーカード at the city office, you set up up to four PINs:
| PIN | Digits | Used for | Lock-out after |
|---|---|---|---|
| 署名用電子証明書 暗証番号 | 6–16 alphanumeric | e-Tax, online document submission | 5 wrong entries |
| 利用者証明用電子証明書 暗証番号 | 4 digits | マイナポータル login, コンビニ交付 | 3 wrong entries |
| 住民基本台帳用 暗証番号 | 4 digits | 住基ネット procedures (administrative use) | 3 wrong entries |
| 券面事項入力補助用 暗証番号 | 4 digits | Reading card data at terminals | 3 wrong entries |
If a PIN is locked out due to too many wrong entries, you must visit the city office to have it reset. You cannot do this online.
Common Mistakes English Speakers Make
Thinking マイナンバー means the card, not the number
Because “My Number Card” is a natural English phrase, some learners assume マイナンバー refers to the physical card. It does not — マイナンバー is the number. The card is マイナンバーカード. When someone says マイナンバーを教えてください, they are asking for your 12 digits, not asking to see your card.
Using 個人番号通知書 as identity verification
The 個人番号通知書 arrives in the mail, looks official, has your name and your number, and feels like a document you should be able to show people. But it is not accepted as 本人確認書類. Showing it at a bank counter or to your HR department as identity proof will result in being asked for something else. Keep it for reference, but do not try to use it as an ID card.
Confusing 番号確認書類 and 本人確認書類
These two terms look similar in Japanese and both involve paperwork, but they answer different questions. 本人確認書類 says who you are. 番号確認書類 says what your number is. An employer legally needs both when onboarding an employee. Having only one type of document — no matter how strong — leaves the process incomplete unless you are using a マイナンバーカード, which answers both at once.
Thinking 通知カード is still newly issued
The 通知カード stopped being issued in May 2020. New residents and new registrations now receive the 個人番号通知書 instead. If a website or article tells you to look for your “通知カード” as a first step, it may be outdated. If you arrived in Japan after May 2020, you will have a 個人番号通知書, not a 通知カード.
Sharing the number too casually
マイナンバーは適切に管理してください — manage your My Number appropriately. Your individual number is sensitive personal information protected under law. You are legally required to provide it only to designated entities: employers, financial institutions, government offices, and a limited list of other parties. Do not write it on documents that do not require it, and do not share it in casual conversation or by email unless the receiving party has a legal basis to collect it.
Forgetting to update the card after moving
If you move to a new address in Japan, you must update your マイナンバーカード. The address on the card must always match your current 住民票. Failing to do so will eventually block you from using コンビニ交付 and other card-based services. The update is done at the city office when you submit your 転入届（てんにゅうとどけ：move-in notification）or 転居届（てんきょとどけ：change-of-address notification）.
Decision Rule: Which My Number Word Do You Need?
Use this flowchart the next time you are unsure which term applies to your situation.
Are you talking about the 12-digit number itself?
→ Everyday conversation or media → マイナンバー
→ Official form or legal document → 個人番号
Are you talking about a physical object (card or paper)?
→ Plastic IC card with photo → マイナンバーカード
→ Paper notification document (mailed to you) → 個人番号通知書
(old postcard-style, pre-May 2020) → 通知カード
Do you need to prove your IDENTITY (who you are)?
→ マイナンバーカード / 運転免許証 / パスポート / 在留カード
These are: 本人確認書類
Do you need to prove your NUMBER (what it is)?
→ マイナンバーカード (alone is enough)
→ 通知カード + 本人確認書類 (if current address matches)
→ 住民票の写し（個人番号入り）+ 本人確認書類
These are: 番号確認書類
Can you use 個人番号通知書 for anything official?
→ No. Keep it for reference only.
Simplest option for employment / banking / city hall?
→ Get a マイナンバーカード. One card satisfies all requirements.Is this tax, employment, city hall, bank, or online procedure language?
| Situation | Word you need | Document to bring / submit |
|---|---|---|
| New employee paperwork (HR) | マイナンバー（個人番号）を提出する | マイナンバーカード (best) or 本人確認書類 + 番号確認書類 |
| Year-end tax adjustment form | 個人番号 を記入する | Check your card or 住民票 for the number |
| Tax return (確定申告) | 個人番号 を申告書に記載する | マイナンバーカード for e-Tax; number on paper form |
| Opening a bank account | マイナンバー（個人番号）の提出 | マイナンバーカード recommended |
| City hall counter (any procedure) | 本人確認書類 and possibly 番号確認書類 | マイナンバーカード (one-stop) |
| マイナポータル login | マイナンバーカード (physical card required) | 4-digit 利用者証明用電子証明書 PIN |
| e-Tax online filing | 署名用電子証明書 (on マイナンバーカード) | マイナンバーカード + 6–16 character PIN |
| Convenience store certificate | コンビニ交付 (マイナンバーカード required) | Card + 4-digit 利用者証明用 PIN |
Ready to practice your Japanese in real conversations? italki connects you with native Japanese tutors who can walk you through bureaucratic Japanese, HR vocabulary, and the kind of practical language this article covers — one conversation at a time.
Quick Quiz
Test yourself on the four key terms. Answers are below.
Q1. You are filling out your tax return and see a blank field labeled 個人番号（12桁）. What do you write?
a) The word “マイナンバー”
b) Your 12-digit individual number
c) Your passport number
Q2. Your employer says: マイナンバーカードか、本人確認書類と番号確認書類の組み合わせを提出してください. You only have your driver's licence and your 個人番号通知書. Can you complete the submission?
a) Yes, driver's licence = 本人確認 and 個人番号通知書 = 番号確認
b) No, 個人番号通知書 is not accepted as a 番号確認書類
c) Yes, the 個人番号通知書 counts as both
Q3. Which of the following can be used alone to satisfy both 本人確認 AND 番号確認 at the same time?
a) 個人番号通知書
b) 通知カード
c) マイナンバーカード
Q4. A friend moved to Japan after May 2020. What document will they have received in the mail about their individual number?
a) 通知カード
b) マイナンバーカード
c) 個人番号通知書
Q5. You want to print your residence certificate at a Lawson convenience store at 8 PM. What do you need?
a) 個人番号通知書 and your name
b) マイナンバーカード and your 4-digit 利用者証明用電子証明書 PIN
c) Your 通知カード and passport
Q6. On an official health insurance enrollment form, will you see the field labeled マイナンバー or 個人番号?
a) マイナンバー
b) 個人番号
c) Either; both are acceptable
Answers: Q1: b — Q2: b — Q3: c — Q4: c — Q5: b — Q6: b
If you found this article useful, leave a comment below and let us know which situation first made you look up the difference. Your experience might help the next reader.
Keep Learning
These articles continue building your practical Japanese vocabulary for everyday life in Japan:
