PUBLISHED AUGUST 20267 MIN READ健康保険法 · 国民年金法 · 所得税法
THREE LAYERS, THEN THREE DEFINITIONSTHE NUMBER OF DEPENDENTS DOES NOT CHANGE THE PREMIUM
1
Insurer保険者
Operates the scheme and pays the benefits — 全国健康保険協会 or a health-insurance society. Never the employer.
2
Insured person被保険者
The employee used at a covered workplace. Pays the premium.
3
Dependent被扶養者
A family member maintained by the insured, covered with no added premium — the count of dependents does not change what is charged.
NOT A LAYER · 被用者保険だけの概念
国民健康保険には「扶養」がない
National Health Insurance has no dependent status at all. Every family member is an insured person in their own right, and the total premium rises with each one.
→ THE STATUS DISAPPEARS ON THE MOVE
Health insurance runs on three layers: the insurer (保険者) that operates the scheme and pays benefits; the insured person (被保険者) — the employee at a covered workplace, who pays the premium; and the dependent (被扶養者) — a family member maintained by the insured, covered without any added premium.
The word “dependent” then splits. Health insurance, pension and tax each define it separately — different relatives, different income limits, different deciders. The same person can be a dependent for one and not for another.
1
Three “dependents”
扶養の3基準 — SEPARATELY DEFINED, SEPARATELY DECIDED
健康保険の被扶養者 HEALTH-INSURANCE DEPENDENT
国民年金 第3号被保険者 CATEGORY III INSURED PERSON
税法上の扶養親族 DEPENDENT RELATIVE
Who can be one
Relatives within the 3rd degree, plus a common-law spouse’s parents and children — some with a same-household condition.
A SINGLE NARROW WINDOWOnly a dependent spouse aged 20–59.
Blood relatives within 6 degrees and relatives by marriage within 3 — a far wider net.
Main income test
BROADER THAN TAXABLE PAYAnnual income under ¥1.3M (¥1.8M if 60+ or with a qualifying disability; ¥1.5M for ages 19–22 from Oct 2025). Includes pensions, benefits and non-taxable income.
Rides on the health-insurance dependent test — but only within the 20–59 age window.
A ceiling based on total income amount under tax law — a different measure entirely.
What it gives
Medical cover at no added premium.
Pension-contribution months with no premium paid.
May qualify the taxpayer for a dependent deduction, subject to age and other tax rules.
Who decides
The insurer.
Japan Pension Service, via the employer.
The tax office, or the year-end adjustment.
2
The health-insurance dependent, precisely
被扶養者の範囲と要件
01 · NO SAME-HOUSEHOLD CONDITION 同居不要
Maintained by the insured is enough: spouse (including common-law), lineal ascendants (parents, grandparents), children and grandchildren, and siblings. Siblings were aligned with this group in October 2016.
02 · SAME HOUSEHOLD REQUIRED 同居が条件
Other relatives within the 3rd degree — a spouse’s parents, uncles and aunts — and a common-law spouse’s parents and children, qualify only if in the same household as the insured.
03 · THE INCOME TEST 収入基準
Under ¥1.3M a year and: if living together, under half the insured’s income; if apart, under the amount remitted to them. The threshold is ¥1.8M (60+, or a qualifying disability) or ¥1.5M (ages 19–22, excluding the spouse, from Oct 2025). “Income” here includes pensions, unemployment and sickness benefits — not only taxable pay.
04 · RESIDENCE IN JAPAN 国内居住要件
In principle the dependent must have an address in Japan (since April 2020). Exceptions cover students studying abroad, family accompanying an overseas posting, and short trips abroad.
3
The spouse’s second door
配偶者だけの別ルート · 第3号被保険者
A spouse dependent on a Category II insured person (the employee) who is aged 20–59 becomes a Category III insured person under the National Pension — gaining pension months without paying any premium. It rides on the health-insurance test but adds an age gate of its own.
RESIDENCE GATE
Since April 2020 the spouse must, in principle, reside in Japan — the same exceptions as the dependent test apply.
FOREIGN SPOUSES
A non-Japanese spouse aged 20–59 cannot be Category III where their status of residence is “Designated Activities” for medical stay, or for long-stay tourism / a long-stayer’s accompanying spouse — even with an address in Japan.
Health-insurance dependent ≠ Category III. The link is conditional, not automatic: spouse only, ages 20–59, resident in Japan, and not on a status of residence that bars it.
4
An employees’ scheme
健康保険は被用者保険 — 雇われていない人は国保へ
WHO IT IS FOR
Health insurance (協会けんぽ or a health-insurance society) is for people who are employed — those used at a covered workplace become insured persons.
THE INSURER, NOT THE EMPLOYER
The employer is not the insurer. The scheme is run by the 全国健康保険協会 or a health-insurance society; the employer withholds and files.
NOT COVERED → 国民健康保険
Those not covered by employees’ health insurance — the self-employed, freelancers, the retired, those not enrolled at work — generally fall to National Health Insurance, unless another public medical-insurance route applies.
国保 HAS NO “DEPENDENT”
National Health Insurance has no dependent status at all. Every family member is an insured person, and the total premium rises with each one.
The trap: “they’re my family” answers none of the three questions. A parent may be a health-insurance dependent yet outside the tax measure; a spouse may clear the health-insurance test yet fall outside Category III for being 60, or for a status of residence that bars it.
FOUR EQUATIONS THAT DO NOT HOLD成り立たない四つの等式
≠
Dependent ≠ tax dependent 健保の扶養と税の扶養は別基準
≠
Employer ≠ insurer 勤務先は保険者ではない
≠
Family member ≠ dependent 家族でも扶養とは限らない／国保に扶養はない
≠
Health dependent ≠ Category III 健保の扶養と年金3号は別
FOR THE ENGINE
Do not store “dependent” as one flag.
Run three independent determinations — health, pension, tax — each with its own eligible-relatives set, income rule, and decider; the same person resolves differently across them. And note the entity itself: a “dependent” exists only in the employees’ scheme — National Health Insurance has no such record, only per-person insured entries. The health→Category-III link is conditional, not automatic: spouse only, ages 20–59, resident in Japan, and — for a non-Japanese spouse — not on a status of residence that bars it. The insurer is the 協会けんぽ or a society, never the employer. Income for the health test is broader than taxable pay: pensions and benefits count.
WHO WRITES THESE
Wakana Chiba, Tokutei Sharoushi
Licensed Labor and Social Security Attorney in Japan
Wakana Chiba is a Tokutei Sharoushi — a nationally qualified and registered Labor and Social Security Attorney in Japan. She advises employers on Japanese employment law, workplace rules, working time, employment documentation, and labor and social insurance procedures, translating complex statutory requirements into policies and operations that work in practice.
Legal analysis and review of Japanese primary sources are performed by Wakana Chiba. English terminology is checked against the Japanese Law Translation Database and official MHLW materials. While AI may be used to draft initial texts, all published conclusions have been reviewed by the author.
TSUKURU-HR.COM / GLOBAL · COOKIE POLICY協会けんぽ = JAPAN HEALTH INSURANCE ASSOCIATION · 国保 = NATIONAL HEALTH INSURANCE · INCOME AND AGE THRESHOLDS CHANGE OFTEN — CONFIRM CURRENT FIGURES BEFORE RELYING ON THEM · AS OF AUGUST 2026 · GENERAL INFORMATION, NOT LEGAL ADVICE
