# 所得税法 / Income Tax Act — 附　則 (Supplementary Provisions)

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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: 附　則 (Supplementary Provisions) — address `suppl-4121-21`
- Text in force since: 2026-10-01
- URL (the page that opens at this provision): https://japanlaw.org/en/income-tax-act/suppl-4121-21
- 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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## 附　則 平成一二年三月三一日法律第二一号
<sup>suppl-4121-21 · https://japanlaw.org/en/income-tax-act/suppl-4121-21</sup>

### 第一条（施行期日等） — Effective Date, etc.
<sup>caption: machine translation, not official</sup>
<sup>suppl-4121-21/art-1 · https://japanlaw.org/en/income-tax-act/suppl-4121-21/art-1</sup>

**第一項**  この法律は、平成十二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、それぞれ当該各号に定める日から施行する。
<sup>suppl-4121-21/art-1/par-1 · https://japanlaw.org/en/income-tax-act/suppl-4121-21/art-1/par-1</sup>
This Act comes into effect on April 1, 2000; provided, however, that the provisions set forth in the following items come into effect on the dates specified respectively in those items:
<sup>machine translation, not official</sup>

  **一から三まで**  略
  <sup>suppl-4121-21/art-1/par-1/item-1-to-3 · https://japanlaw.org/en/income-tax-act/suppl-4121-21/art-1/par-1/item-1-to-3</sup>
  Omitted
  <sup>machine translation, not official</sup>

  **四**  第二条（次号に掲げる規定を除く。）、第四条（国家公務員等共済組合法等の一部を改正する法律附則第九条第一項、第十五条及び附則別表第二の改正規定に限る。）、第六条（前号に掲げる規定を除く。）並びに附則第十条から第十二条まで、第十四条、第十五条、第十九条、第二十条及び第二十二条の規定　平成十五年四月一日
  <sup>suppl-4121-21/art-1/par-1/item-4 · https://japanlaw.org/en/income-tax-act/suppl-4121-21/art-1/par-1/item-4</sup>
  the provisions of Article 2 (excluding the provisions set forth in the following item), Article 4 (limited to the provisions amending Article 9, paragraph (1), Article 15, and Appended Table 2 of the Supplementary Provisions of the Act Partially Amending the National Public Servants, etc. Mutual Aid Association Act, etc.), and Article 6 (excluding the provisions set forth in the preceding item), and the provisions of Articles 10 through 12, 14, 15, 19, 20, and 22 of the Supplementary Provisions: April 1, 2003;
  <sup>machine translation, not official</sup>

### 第二十条（所得税法の一部改正に伴う経過措置） — Transitional Measures Accompanying the Partial Amendment of the Income Tax Act
<sup>caption: machine translation, not official</sup>
<sup>suppl-4121-21/art-20 · https://japanlaw.org/en/income-tax-act/suppl-4121-21/art-20</sup>

**第一項**  第二条の規定による改正前の法第百一条の二第一項の規定による特別掛金は、前条の規定による改正後の所得税法第七十四条第二項第九号の社会保険料とみなして、同法の規定を適用する。
<sup>suppl-4121-21/art-20/par-1 · https://japanlaw.org/en/income-tax-act/suppl-4121-21/art-20/par-1</sup>
Special installments under Article 101-2, paragraph (1) of the Act prior to amendment by the provisions of Article 2 are deemed to be social insurance premiums under Article 74, paragraph (2), item (ix) of the Income Tax Act as amended by the provisions of the preceding Article, and the provisions of that Act apply.
<sup>machine translation, not official</sup>

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## Cites
- suppl-4121-21/art-1/par-1/item-4: 第二十条 → 所得税法 附則第二十条 (Supplementary Provisions, Article 20), suppl-4121-21/art-20 — https://japanlaw.org/en/income-tax-act/suppl-4121-21/art-20
- suppl-4121-21/art-20/par-1: 所得税法第七十四条第二項第九号 → 所得税法 第七十四条第二項第九号 (Article 74, paragraph (2), item (ix)), art-74/par-2/item-9 — https://japanlaw.org/en/income-tax-act/art-74/par-2/item-9

## Cited by

1 provision cites this one. No official source publishes this direction.

- 所得税法 附則第一条第一項第四号（施行期日等） — https://japanlaw.org/en/income-tax-act/suppl-4121-21/art-1/par-1/item-4

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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-20260918T180319-084, 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