# 所得税法施行令 / Order for Enforcement of the Income Tax Act — 第百六十五条 (Article 165)
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- Law: 所得税法施行令 (Order for Enforcement of the Income Tax Act), 昭和四十年政令第九十六号
- English title "Order for Enforcement of the Income Tax Act": Ministry of Justice translation
- Kind: CabinetOrder — the distinction between 法律 (Act), 政令 (Cabinet Order), 省令 (Ministerial Order) and 条例 (local ordinance) decides who may issue it and what it may say.
- Provision: 第百六十五条 (Article 165)（親族が事業に専ら従事するかどうかの判定） — address `art-165`
- Text in force since: 2026-05-22
- URL (the page that opens at this provision): https://japanlaw.org/en/income-tax-act-enforcement-order/art-165
- e-Gov law ID: 340CO0000000096 — never renamed. A permanent link, `/l/{lawId}/{address}` on this site, redirects to the page.
- Every provision below carries its address and its URL on the line under it.
- Japanese text: e-Gov 法令検索, Digital Agency (デジタル庁). English: as marked on each line below.
Only the Japanese as published by the government has legal effect; the text
below is a copy of it. Every English rendering below is a translation and
says which kind: the Ministry of Justice's translation, or this
site's machine translation, whose model and date the Sources list names.
They are never merged and never substituted for one another.
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### 第百六十五条（親族が事業に専ら従事するかどうかの判定） — Determination of Whether a Relative Is Exclusively Engaged in a Business
caption: machine translation, not official
art-165 · https://japanlaw.org/en/income-tax-act-enforcement-order/art-165
**第一項** 法第五十七条第一項又は第三項（事業に専従する親族がある場合の必要経費の特例等）に規定する居住者と生計を一にする配偶者その他の親族が専らその居住者の営むこれらの規定に規定する事業に従事するかどうかの判定は、当該事業に専ら従事する期間がその年を通じて六月をこえるかどうかによる。ただし、同条第一項の場合にあつては、次の各号のいずれかに該当するときは、当該事業に従事することができると認められる期間を通じてその二分の一に相当する期間をこえる期間当該事業に専ら従事すれば足りるものとする。
art-165/par-1 · https://japanlaw.org/en/income-tax-act-enforcement-order/art-165/par-1
The determination of whether a spouse or other relative who shares livelihood with a Resident prescribed in Article 57, paragraph (1) or (3) (Special Provisions on Necessary Expenses If Relatives Work Exclusively for a Resident) of the Act is exclusively engaged in the business that the Resident carries on as prescribed in those provisions is made according to whether the period of exclusive engagement in that business exceeds six months in the year; provided, however, that in the case of paragraph (1) of that Article, where the case falls under any of the following items, it suffices that the relative is exclusively engaged in that business for a period exceeding one-half of the period during which the relative is found to be able to engage in that business.
machine translation, not official
**一** 当該事業が年の中途における開業、廃業、休業又はその居住者の死亡、当該事業が季節営業であることその他の理由によりその年中を通じて営まれなかつたこと。
art-165/par-1/item-1 · https://japanlaw.org/en/income-tax-act-enforcement-order/art-165/par-1/item-1
that business was not carried on throughout the year because of the commencement, closure or suspension of the business or the death of the Resident in the middle of the year, the seasonal nature of the business, or other reasons;
machine translation, not official
**二** 当該事業に従事する者の死亡、長期にわたる病気、婚姻その他相当の理由によりその年中を通じてその居住者と生計を一にする親族として当該事業に従事することができなかつたこと。
art-165/par-1/item-2 · https://japanlaw.org/en/income-tax-act-enforcement-order/art-165/par-1/item-2
the person engaged in that business was unable to engage in it throughout the year as a relative sharing livelihood with the Resident because of death, long-term illness, marriage or other reasonable grounds.
machine translation, not official
**第二項** 前項の場合において、同項に規定する親族につき次の各号の一に該当する者である期間があるときは、当該期間は、同項に規定する事業に専ら従事する期間に含まれないものとする。
art-165/par-2 · https://japanlaw.org/en/income-tax-act-enforcement-order/art-165/par-2
In the case referred to in the preceding paragraph, where there is a period during which a relative prescribed in that paragraph is a person falling under any one of the following items, that period is not included in the period of exclusive engagement in the business prescribed in that paragraph.
machine translation, not official
**一** 学校教育法第一条（学校の範囲）、第百二十四条（専修学校）又は第百三十四条第一項（各種学校）の学校の学生又は生徒である者（夜間において授業を受ける者で昼間を主とする当該事業に従事するもの、昼間において授業を受ける者で夜間を主とする当該事業に従事するもの、同法第百二十四条又は同項の学校の学生又は生徒で常時修学しないものその他当該事業に専ら従事することが妨げられないと認められる者を除く。）
art-165/par-2/item-1 · https://japanlaw.org/en/income-tax-act-enforcement-order/art-165/par-2/item-1
a person who is a student or pupil of a school under Article 1 (Scope of Schools), Article 124 (Specialized Training Colleges) or Article 134, paragraph (1) (Miscellaneous Schools) of the School Education Act (excluding a person who attends classes at night and engages in that business mainly in the daytime, a person who attends classes in the daytime and engages in that business mainly at night, a student or pupil of a school under Article 124 or Article 134, paragraph (1) of that Act who does not attend regularly, and any other person found not to be prevented from engaging exclusively in that business);
machine translation, not official
**二** 他に職業を有する者（その職業に従事する時間が短い者その他当該事業に専ら従事することが妨げられないと認められる者を除く。）
art-165/par-2/item-2 · https://japanlaw.org/en/income-tax-act-enforcement-order/art-165/par-2/item-2
a person who has another occupation (excluding a person whose time engaged in that occupation is short and any other person found not to be prevented from engaging exclusively in that business);
machine translation, not official
**三** 老衰その他心身の障害により事業に従事する能力が著しく阻害されている者
art-165/par-2/item-3 · https://japanlaw.org/en/income-tax-act-enforcement-order/art-165/par-2/item-3
a person whose ability to engage in a business is significantly impaired by senility or other mental or physical disability.
machine translation, not official
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## Cites
- art-165/par-1: 法第五十七条第一項 → 所得税法 第五十七条第一項 (Article 57, paragraph (1)), art-57/par-1 — https://japanlaw.org/en/income-tax-act/art-57/par-1 (e-Gov law ID 340AC0000000033)
- art-165/par-1: 第三項 → 所得税法 第五十七条第三項 (Article 57, paragraph (3)), art-57/par-3 — https://japanlaw.org/en/income-tax-act/art-57/par-3 (e-Gov law ID 340AC0000000033)
- art-165/par-2: 前項 → 所得税法施行令 第百六十五条第一項 (Article 165, paragraph (1)), art-165/par-1 — https://japanlaw.org/en/income-tax-act-enforcement-order/art-165/par-1
- art-165/par-2/item-1: 学校教育法第一条 → 学校教育法 第一条 (Article 1), art-1 — https://japanlaw.org/en/school-education-act/art-1 (e-Gov law ID 322AC0000000026)
- art-165/par-2/item-1: 第百二十四条 → 学校教育法 第百二十四条 (Article 124), art-124 — https://japanlaw.org/en/school-education-act/art-124 (e-Gov law ID 322AC0000000026)
- art-165/par-2/item-1: 第百三十四条第一項 → 学校教育法 第百三十四条第一項 (Article 134, paragraph (1)), art-134/par-1 — https://japanlaw.org/en/school-education-act/art-134/par-1 (e-Gov law ID 322AC0000000026)
## Cited by
2 provisions cite this one. No official source publishes this direction.
- 所得税法施行令 第百六十五条第二項（親族が事業に専ら従事するかどうかの判定） — https://japanlaw.org/en/income-tax-act-enforcement-order/art-165/par-2
- 所得税法施行令 附則第十条第一項（輸出所得の特別控除があつた場合の事業専従者給与等の必要経費算入額等の計算に関する経過規定） — https://japanlaw.org/en/income-tax-act-enforcement-order/suppl-3402-96/art-10/par-1
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## Sources
- e-Gov 法令検索, Digital Agency (デジタル庁) — 所得税法施行令 — the text in force from 2026-05-22 (https://laws.e-gov.go.jp/law/340CO0000000096/20260522_508CO0000000093), retrieved 2026-11-06
- Japanese Law Translation Database System, Ministry of Justice (法務省) — Order for Enforcement of the Income Tax Act — Ministry of Justice translation (https://www.japaneselawtranslation.go.jp/en/laws/view/3121/tb), retrieved 2026-11-06
- claude-sonnet-5-5 — Machine translation, batch income-tax-act-enforcement-order-20261106T173921-042, translated 2026-11-07
- claude-sonnet-5-5, corrected on review by claude-opus-5-5 — Machine translation corrected on review, batch income-tax-act-enforcement-order-20261106T173921-042, translated 2026-11-07
- This site's parser, version 229 — 所得税法施行令 — structure, counts, cross-references and defined terms, computed 2026-11-06