● Health Insurance / Lump-sum benefit
● No income limit

Your health insurance pays¥500,000 per child when you give birth

Official name
Lump-sum childbirth allowance — Kyokai Kenpo (出産育児一時金)

If you (or your dependent spouse) are insured under Kyokai Kenpo (Japan Health Insurance Association — the most common employee-based insurance in Japan) and give birth, your insurance pays ¥500,000 per child.

With the "direct-pay" system (直接支払制度), Kyokai Kenpo pays the allowance straight to the hospital, so you only pay the remainder at discharge. If your delivery costs less than ¥500,000, Kyokai Kenpo mails you a form about 3 months after the birth so you can claim the difference.

PER CHILD
500,000JPY
For births on or after April 1, 2023, at hospitals enrolled in the Obstetric Compensation System (most hospitals in Tokyo) and with a gestation of 22+ weeks. Earlier than 22 weeks, or non-enrolled hospitals: ¥488,000. Multiple births: per-child amount × number of children.

Who can claim this

Anyone covered by Kyokai Kenpo as the insured person or as their spouse/dependent.

As the insured employee
You are paying Kyokai Kenpo through your job (your monthly salary slip shows 健康保険料 deductions). The lump sum applies to your own birth.
As a dependent spouse
Your spouse is the insured employee, and you are registered as their dependent (扶養者) under Kyokai Kenpo. You receive the same ¥500,000 — called "family lump-sum childbirth allowance" (家族出産育児一時金).
No income cap, no nationality requirement
Anyone covered by Kyokai Kenpo can claim. There is no household income limit. The benefit is paid regardless of nationality, as long as you are properly enrolled in the insurance.

The direct-pay system (default flow)

If your hospital uses the direct-pay system, you usually do not need to file the ¥500,000 claim yourself.

BEFORE BIRTH
Show your health insurance card at the hospital
Confirms you are enrolled in Kyokai Kenpo. The hospital uses this for billing.
STEP 1
Sign the "direct-pay agreement" (直接支払制度同意書)
Provided by the hospital, usually at admission or before discharge. By signing, the ¥500,000 flows directly from your insurance to the hospital.
STEP 2
Give birth, then pay only the difference at checkout
If hospital bill = ¥800,000, you pay ¥800,000 − ¥500,000 = ¥300,000. If bill is less than ¥500,000 (e.g. ¥450,000), you pay nothing now; you claim the ¥50,000 difference afterwards (STEP 3).
STEP 3 (only if balance owed to you)
Claim the difference from Kyokai Kenpo
About 3 months after the birth, Kyokai Kenpo mails the insured person the difference claim form (出産育児一時金差額申請書). Fill it in and send it to your Kyokai Kenpo branch. (How long the payment takes after that is not stated on the official page.)
Alternative: post-payment claim (事後申請). If you do not use direct-pay, pay the full cost to the hospital by discharge and then claim the allowance yourself from Kyokai Kenpo (claims expire after 2 years — Article 193 of the Health Insurance Act). Some hospitals registered with MHLW instead offer the "receipt-by-proxy" system (受取代理制度), which you can apply for within 2 months before your due date.

Common questions

What if I have twins or triplets?
Per-child amount × number of children. Twins = ¥1,000,000. Triplets = ¥1,500,000. Multiple births at hospitals not enrolled in the Obstetric Compensation System or before 22 weeks: ¥488,000 × number of children.
What about miscarriage or stillbirth?
Births, stillbirths, miscarriages and abortions after 85 days (4 months) of pregnancy are covered. At 22 weeks or later at an enrolled facility the amount is ¥500,000; earlier than 22 weeks, or at a non-enrolled facility, it is ¥488,000 (the base figure in Article 36 of the Health Insurance Act Enforcement Order).
My partner is on Kyokai Kenpo and I'm a dependent — who claims it?
The insured spouse (your partner) is the formal claimant, but the funds and the direct-pay system work the same way. The benefit is called "family lump-sum childbirth allowance" (家族出産育児一時金) but the amount is identical.
How does this combine with the Minato birth-cost subsidy?
They stack. Kyokai Kenpo pays ¥500,000 first; if your hospital bill exceeds that, the Minato Ward birth-cost subsidy pays the amount above ¥500,000, up to ¥310,000 (singletons; bills above ¥810,000 are capped there).
Application deadline?
The right to claim expires after 2 years from when it can first be exercised (Article 193 of the Health Insurance Act). This also applies to the difference claim under direct-pay, so send it back once it arrives.
I left my job before the birth — can I still get it?
Yes, if you had been insured (not counting voluntary continuation) continuously for 1 year or more up to the day before losing coverage, and you give birth within 6 months after losing coverage. It is paid only once per birth. Note: if a family member who was your dependent gives birth after you lose coverage, the family allowance is not paid.
Can I borrow money before the allowance arrives?
Yes. Kyokai Kenpo lends up to 80% of the allowance interest-free (出産費貸付制度) to people expected to receive it who are within 1 month of the due date, or who are at least 4 months pregnant and must pay the hospital temporarily.

Official sources (in Japanese)

For authoritative answers, please consult Kyokai Kenpo or the e-Gov law database.