第九十条（国庫補助金等に係る固定資産の償却費の計算等）
Article 90Calculation, etc. of Depreciation Allowance for Fixed Assets Pertaining to Government Subsidies and Their Equivalent
The amount calculated pursuant to the provisions of Cabinet Order prescribed in Article 42, paragraph (1) (Exclusion of Government Subsidies and Their Equivalent in Gross Revenue) of the Act is the amount specified in each of the following items for the category of cases listed in that item.
法第四十二条第一項（国庫補助金等の総収入金額不算入）に規定する政令で定めるところにより計算した金額は、次の各号に掲げる場合の区分に応じ当該各号に定める金額とする。
In the case of acquisition of a Depreciable Asset prescribed in Article 42, paragraph (1) of the Act: the amount calculated by multiplying the amount equivalent to the amount of the government subsidy or its equivalent prescribed in that paragraph pertaining to that Depreciable Asset (hereinafter in this Article referred to as "government subsidy or its equivalent") by the ratio that the amount set out in (b) bears to the amount set out in (a):
the amount required for the acquisition of that Depreciable Asset;
当該減価償却資産の取得に要した金額
the amount obtained by deducting, from the amount required for the acquisition of that Depreciable Asset, the cumulative amount of the depreciation allowance calculated on the basis of that amount, in accordance with the provisions of Article 49, paragraph (1) (Calculating Depreciation Allowances for Depreciable Assets; Depreciation Methods) of the Act, for the period from the date of its acquisition to the date on which return of the government subsidy or its equivalent ceased to be required;
In the case of improvement of a Depreciable Asset prescribed in Article 42, paragraph (1) of the Act: the amount calculated by multiplying the amount equivalent to the amount of the government subsidy or its equivalent pertaining to that Depreciable Asset by the ratio that the amount set out in (b) bears to the amount set out in (a):
the amount required for the improvement of that Depreciable Asset;
当該減価償却資産の改良に要した金額
the amount obtained by deducting, from the amount required for the improvement of that Depreciable Asset, the cumulative amount of the depreciation allowance calculated on the basis of that amount, in accordance with the provisions of Article 49, paragraph (1) of the Act, for the period from the date of its improvement to the date on which return of the government subsidy or its equivalent ceased to be required.
The calculation of the depreciation allowance prescribed in Article 49, paragraph (1) of the Act that is to be made for a Fixed Asset (including timberland; the same applies hereinafter in this paragraph and in paragraph (2) of the following Article) to which the provisions of Article 42, paragraph (1) or (2) of the Act apply, and the calculation of the amount of business income, amount of timber income, amount of capital gains, or amount of miscellaneous income in the case where there has been a transfer of that Fixed Asset, are as provided in the following items.
With regard to a Fixed Asset to which the provisions of Article 42, paragraph (1) of the Act apply, the Fixed Asset is deemed to have been acquired or improved at the amount obtained by deducting the amount equivalent to the amount of the government subsidy or its equivalent pertaining to that Fixed Asset from the amount required for its acquisition (for timberland, the amount of planting costs; the same applies in the following item and in paragraph (2) of the following Article) or the amount equivalent to the amount of improvement expenses, and the amount equivalent to the amount obtained by deducting the amount specified in item (i) or (ii) of the preceding paragraph from the amount equivalent to the amount of the government subsidy or its equivalent is deemed not to have been included in necessary expenses in calculating the amount of real property income, amount of business income, amount of timber income, or amount of miscellaneous income for each year as that depreciation allowance for the period prescribed in item (i), (b) or item (ii), (b) of that paragraph;
With regard to a Fixed Asset prescribed in Article 42, paragraph (2) of the Act, the amount required for its acquisition is deemed to be nil.
法第四十二条第二項に規定する固定資産については、その固定資産の取得に要した金額は、ないものとみなす。
略称規定第九十条第一項第一号・この条の中だけ
法第四十二条第一項の減価償却資産の取得をした場合 当該減価償却資産に係る同項に規定する国庫補助金等（以下この条において「国庫補助金等」という。）の額に相当する金額に、イに掲げる金額のうちにロに掲げる金額の占める割合を乗じて計算した金額
わかりやすく言うと
固定資産（山林を含む）の取得又は改良に充てるための、国又は地方公共団体の補助金又は給付金と、これらに準ずるものとして政令で定めるもののことです（所得税法第四十二条第一項）。