# 所得税法 / Income Tax Act — 第一条 (Supplementary Provisions, Article 1)

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- Law: 所得税法 (Income Tax Act), 昭和四十年法律第三十三号
- English title "Income Tax Act": Ministry of Justice translation
- Kind: Act — 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: 第一条 (Supplementary Provisions, Article 1)（施行期日） — address `suppl-5051-3/art-1`
- Text in force since: 2026-10-01
- URL (the page that opens at this provision): https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1
- e-Gov law ID: 340AC0000000033 — 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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### 第一条（施行期日） — Effective Date
<sup>caption: machine translation, not official</sup>
<sup>suppl-5051-3/art-1 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1</sup>

**第一項**  この法律は、令和五年四月一日から施行する。ただし、次の各号に掲げる規定は、当該各号に定める日から施行する。
<sup>suppl-5051-3/art-1/par-1 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1</sup>
This Act comes into effect on April 1, 2023; provided, however, that the provisions set forth in the following items come into effect on the dates specified in those items:
<sup>machine translation, not official</sup>

  **一から四まで**  略
  <sup>suppl-5051-3/art-1/par-1/item-1-to-4 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1/item-1-to-4</sup>
  Omitted
  <sup>machine translation, not official</sup>

  **五**  次に掲げる規定　令和七年一月一日
  <sup>suppl-5051-3/art-1/par-1/item-5 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1/item-5</sup>
  the following provisions: January 1, 2025;
  <sup>machine translation, not official</sup>

    **イ**  第一条中所得税法第百八十五条第一項の改正規定、同法第百八十七条の改正規定、同法第百九十条の改正規定、同法第百九十四条の改正規定、同法第百九十五条の改正規定、同法別表第二の改正規定、同法別表第三の改正規定及び同法別表第四の改正規定並びに附則第六条の規定
    <sup>suppl-5051-3/art-1/par-1/item-5/sub-1 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1/item-5/sub-1</sup>
    the provision of Article 1 amending Article 185, paragraph (1) of the Income Tax Act, the provision amending Article 187 of that Act, the provision amending Article 190 of that Act, the provision amending Article 194 of that Act, the provision amending Article 195 of that Act, the provision amending Appended Table 2 of that Act, the provision amending Appended Table 3 of that Act and the provision amending Appended Table 4 of that Act, and the provisions of Article 6 of the Supplementary Provisions;
    <sup>machine translation, not official</sup>

  **六**  次に掲げる規定　令和八年一月一日
  <sup>suppl-5051-3/art-1/par-1/item-6 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1/item-6</sup>
  the following provisions: January 1, 2026;
  <sup>machine translation, not official</sup>

    **イ**  第一条中所得税法第百五十一条の改正規定、同法第二百二十九条の改正規定及び同法第二百三十条の改正規定並びに附則第五条及び第十条の規定
    <sup>suppl-5051-3/art-1/par-1/item-6/sub-1 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1/item-6/sub-1</sup>
    the provision of Article 1 amending Article 151 of the Income Tax Act, the provision amending Article 229 of that Act and the provision amending Article 230 of that Act, and the provisions of Articles 5 and 10 of the Supplementary Provisions;
    <sup>machine translation, not official</sup>

  **七**  略
  <sup>suppl-5051-3/art-1/par-1/item-7 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1/item-7</sup>
  Omitted
  <sup>machine translation, not official</sup>

  **八**  次に掲げる規定　令和九年一月一日
  <sup>suppl-5051-3/art-1/par-1/item-8 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1/item-8</sup>
  the following provisions: January 1, 2027;
  <sup>machine translation, not official</sup>

    **イ**  第一条中所得税法第二百二十六条の改正規定及び附則第八条の規定
    <sup>suppl-5051-3/art-1/par-1/item-8/sub-1 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1/item-8/sub-1</sup>
    the provisions in Article 1 amending Article 226 of the Income Tax Act and the provisions of Article 8 of the Supplementary Provisions;
    <sup>machine translation, not official</sup>

  **八の二**  略
  <sup>suppl-5051-3/art-1/par-1/item-8-2 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1/item-8-2</sup>
  Omitted
  <sup>machine translation, not official</sup>

  **九**  次に掲げる規定　安定的かつ効率的な資金決済制度の構築を図るための資金決済に関する法律等の一部を改正する法律（令和四年法律第六十一号）の施行の日
  <sup>suppl-5051-3/art-1/par-1/item-9 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1/item-9</sup>
  the following provisions: the date on which the Act Partially Amending the Payment Services Act, etc. to Establish a Stable and Efficient Funds Settlement System (Act No. 61 of 2022) comes into effect;
  <sup>machine translation, not official</sup>

    **イ**  第一条中所得税法第二十四条第二項ただし書の改正規定、同法第四十八条の二第一項の改正規定、同法第二百二十四条の三の改正規定及び同法第二百二十四条の四の改正規定並びに附則第七条の規定
    <sup>suppl-5051-3/art-1/par-1/item-9/sub-1 · https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-1/par-1/item-9/sub-1</sup>
    the provisions in Article 1 amending the proviso to Article 24, paragraph (2) of the Income Tax Act, amending Article 48-2, paragraph (1) of that Act, amending Article 224-3 of that Act, and amending Article 224-4 of that Act, and the provisions of Article 7 of the Supplementary Provisions;
    <sup>machine translation, not official</sup>

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## Cites
- suppl-5051-3/art-1/par-1/item-5/sub-1: 附則第六条 → 所得税法 附則第六条 (Supplementary Provisions, Article 6), suppl-5051-3/art-6 — https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-6
- suppl-5051-3/art-1/par-1/item-6/sub-1: 附則第五条 → 所得税法 附則第五条 (Supplementary Provisions, Article 5), suppl-5051-3/art-5 — https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-5
- suppl-5051-3/art-1/par-1/item-6/sub-1: 第十条 → 所得税法 附則第十条 (Supplementary Provisions, Article 10), suppl-5051-3/art-10 — https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-10
- suppl-5051-3/art-1/par-1/item-9/sub-1: 附則第七条 → 所得税法 附則第七条 (Supplementary Provisions, Article 7), suppl-5051-3/art-7 — https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-7

## Cited by

2 provisions cite this one. No official source publishes this direction.

- 所得税法 附則第七条第一項（株式等の譲渡の対価の受領者等の告知等に関する経過措置） — https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-7/par-1
- 所得税法 附則第七十八条第一項（罰則に関する経過措置） — https://japanlaw.org/ja/income-tax-act/suppl-5051-3/art-78/par-1

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## Sources

- e-Gov 法令検索, Digital Agency (デジタル庁) — 所得税法 — the text in force from 2026-10-01 (https://laws.e-gov.go.jp/law/340AC0000000033/20261001_507AC0000000070), retrieved 2026-10-05
- Japanese Law Translation Database System, Ministry of Justice (法務省) — Income Tax Act — Ministry of Justice translation (https://www.japaneselawtranslation.go.jp/en/laws/view/3120/tb), retrieved 2026-09-18
- claude-opus-5[1m] — Machine translation, batch income-tax-act-20260918T180319-132, translated 2026-09-18
- claude-opus-5[1m] — Machine translation, batch income-tax-act-20260918T180319-133, translated 2026-09-18
- This site's parser, version 224 — 所得税法 — structure, counts, cross-references and defined terms, computed 2026-10-05