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My Number: What It Is and What It Is Used For

My Number is the 12-digit Individual Number assigned to every person holding a resident record in Japan, including foreign residents.12 It ties your tax, pension, health-insurance, and benefit records to one identifier across agencies.

Confirm current details with official sources

Procedures, fees, and requirements can change. Confirm current details at the Digital Agency site. This article is general information, not tax advice; for your specific case, consult a licensed tax accountant (zeirishi).

Overview​

The 社会保障・税番号制度 (shakai hoshō zei bangō seido, "Social Security and Tax Number System") gives each resident one lifelong number for administrative procedures stipulated by law or ordinance.1 The three statutory fields are social security, tax, and disaster response.2

Operational use of the number started in January 2016.3 Since then it has become the key employers, tax offices, pension bodies, and health insurers ask for whenever a procedure requires identity matching.1

Who gets a My Number​

Everyone with a Japanese resident record gets one. That includes Japanese nationals and mid- to long-term foreign residents alike, because assignment follows the resident record, not nationality.4

Short-stay visitors have no resident record and sit outside the system entirely. If you move to Japan on a work, student, or spouse status and register your address, the number follows automatically.4

Newborns and new arrivals​

Numbers were first designated for residents on the register as of October 5, 2015, and mailed by each municipality.4 Since then, anyone newly registered, through birth or a move-in from abroad, is assigned a number when the resident record is created.4

No separate application exists. Submitting the birth notification or the move-in notification starts the chain, and the municipality notifies you of the number by mail.4

What it is used for​

Agencies and employers collect your number only for procedures the law or an ordinance names.1 Three groups of uses cover nearly every request you will meet.

Tax procedures​

Your employer asks for the number for year-end adjustment and withholding records. When you file an income-tax return yourself, you write the number on the return form and present identification documents or attach copies.5

The My Number Card alone satisfies the check. Without the card, the fallback is the notification document plus a photo ID such as a passport.5

Social insurance and pensions​

Pension bodies use the number to match contribution records to the individual. Health insurers and benefit offices use it the same way when you enroll, claim, or report a change.1

Child allowance, childcare benefits, and other municipal payments also run through number-matched records. Registering a public-funds receiving account lets these payments reach you without extra paperwork.1

Banking and cross-border reporting​

Banks record the number for statutory tax reports and overseas wire-transfer statements. The mechanics, including the 2018 collection duty and the FATCA and CRS exchange behind it, belong to the banking article; the point here is that the request at the counter has a statutory basis.6

One number across agencies is the design, not a data pool

The number lets agencies match records about the same person. It does not merge every database into one file, and each collection still needs its own legal basis.1

What it is not​

My Number is not a general-purpose ID for commerce, transit, or membership sign-ups. Private businesses may handle it only where a law or ordinance requires them to, such as payroll and tax reporting.1

The bare number is also not photo identification. A printed 12-digit number proves nothing about who is holding the paper; only the plastic My Number Card, with its photo and chip, works as an ID document.7

How the number relates to the card​

The number and the card are two different things. The number is assigned automatically at resident registration and stays with you for life.4

The plastic card is optional and applied for separately. Losing the card never loses the number; only the physical credential is replaced while the digits stay the same.4

Good to know​

The number is permanent; only the card is replaced​

The same number follows you across moves, job changes, and card renewals for life.4 It changes only where there is a risk of the number being leaked and misused, such as documented fraud or stalking-victim cases.4

Your ward office is the counter, not the number issuer​

Municipalities notify the number and hand over cards that the Japan Agency for Local Authority Information Systems produces.4 Which counter handles your case and whether you need an appointment varies by city, so check your local ward office page before visiting.4

See also​

References​

Footnotes​

  1. Digital Agency. "About My Number System" (English explanation). https://www.digital.go.jp/en/policies/mynumber/explanation ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8

  2. Digital Agency. "FAQ: About My Number System". Last updated 2026-03-25. https://www.digital.go.jp/en/policies/mynumber_faq_01 ↩ ↩2

  3. Personal Information Protection Commission. Commissioner profile note: use of My Number started 2016-01-01 (historical anchor). https://www.ppc.go.jp/en/aboutus/commission/commissioner1 ↩

  4. Digital Agency. "FAQ: My Number (Individual Number)". Last updated 2026-03-25. https://www.digital.go.jp/en/policies/mynumber_faq_02 ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11

  5. National Tax Agency. 2018 Income Tax Guide (final return Form B; My Number entry and ID documents). https://www.nta.go.jp/english/taxes/individual/pdf/incometax_2018/01.pdf ↩ ↩2

  6. National Tax Agency. "Proper and Fair Taxation and Collection" (2018 annual report excerpt; CRS exchange, wire records). https://www.nta.go.jp/english/Report_pdf/2018e_06.pdf ↩

  7. Digital Agency. "About My Number Card". Last updated 2026-05-26. https://www.digital.go.jp/en/policies/mynumber/pros-and-safety ↩