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

This is the Markdown twin of https://japanlaw.org/ja/income-tax-act/suppl-4181-1. Every law, and how to address a provision: https://japanlaw.org/llms.txt. The same laws as MCP tools (no sign-in): https://japanlaw.org/mcp.

- 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-4181-1`
- Text in force since: 2026-10-01
- URL (the page that opens at this provision): https://japanlaw.org/ja/income-tax-act/suppl-4181-1
- Permanent URL (e-Gov law ID, never renamed): https://japanlaw.org/l/340AC0000000033/suppl-4181-1
- Every provision below carries its address and both URLs 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 平成一八年二月一〇日法律第一号
<sup>suppl-4181-1 · https://japanlaw.org/ja/income-tax-act/suppl-4181-1 · https://japanlaw.org/l/340AC0000000033/suppl-4181-1</sup>

### 第一条（施行期日） — Effective Date
<sup>caption: machine translation, not official</sup>
<sup>suppl-4181-1/art-1 · https://japanlaw.org/ja/income-tax-act/suppl-4181-1/art-1 · https://japanlaw.org/l/340AC0000000033/suppl-4181-1/art-1</sup>

**第一項**  この法律は、平成十八年四月一日から施行する。
<sup>suppl-4181-1/art-1/par-1 · https://japanlaw.org/ja/income-tax-act/suppl-4181-1/art-1/par-1 · https://japanlaw.org/l/340AC0000000033/suppl-4181-1/art-1/par-1</sup>
This Act comes into effect on April 1, 2006.
<sup>machine translation, not official</sup>

### 第二十五条（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-4181-1/art-25 · https://japanlaw.org/ja/income-tax-act/suppl-4181-1/art-25 · https://japanlaw.org/l/340AC0000000033/suppl-4181-1/art-25</sup>

**第一項**  施行日前に支払うべき前条の規定による改正前の所得税法第七十四条第二項第十二号に掲げる納付金については、なお従前の例による。
<sup>suppl-4181-1/art-25/par-1 · https://japanlaw.org/ja/income-tax-act/suppl-4181-1/art-25/par-1 · https://japanlaw.org/l/340AC0000000033/suppl-4181-1/art-25/par-1</sup>
The provisions then in force continue to govern payments set forth in Article 74, paragraph (2), item (xii) of the Income Tax Act before amendment by the preceding Article which are payable before the effective date.
<sup>machine translation, not official</sup>

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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-20260918T180319-096, translated 2026-09-18
- This site's parser, version 223 — 所得税法 — structure, counts, cross-references and defined terms, computed 2026-10-05