法令翻訳 http://www.japaneselawtranslat...ky=&page=3

(資産損失の必要経費算入)
第五十一条  居住者の営む不動産所得、事業所得又は山林所得を生ずべき事業の用に供される固定資産その他これに準ずる資産で政令で定めるものについて、取りこわし、除却、滅失（当該資産の損壊による価値の減少を含む。）その他の事由により生じた損失の金額（保険金、損害賠償金その他これらに類するものにより補てんされる部分の金額及び資産の譲渡により又はこれに関連して生じたものを除く。）は、その者のその損失の生じた日の属する年分の不動産所得の金額、事業所得の金額又は山林所得の金額の計算上、必要経費に算入する。

Inclusion of Losses on Assets in Necessary Expenses
Article 51  A loss incurred due to circumstances such as the demolition, removal, or destruction (including a decrease in value due to damage) of a Fixed Asset, or of any other equivalent asset as provided by Cabinet Order, which is used in a business run by a Resident that is meant to generate real property income, business income, or timber income (other than any part of the loss covered by insurance benefits, compensation for damage, or anything similar to these, and excluding loss due to or related to the transfer of an asset) is included in the necessary expenses that are used to calculate the Resident's real property income, business income, or timber income for the year in which the day of the loss falls.

居住者の営む不動産所得、事業所得又は山林所得を生ずべき事業について、その事業の遂行上生じた売掛金、貸付金、前渡金その他これらに準ずる債権の貸倒れその他政令で定める事由により生じた損失の金額は、その者のその損失の生じた日の属する年分の不動産所得の金額、事業所得の金額又は山林所得の金額の計算上、必要経費に算入する。

A loss incurred in the course of business due to accounts receivable, loans, advance payments, or bad debt claims equivalent to these, or due to other circumstances as provided by Cabinet Order, in a business run by a Resident which is meant to generate real property income, business income, or timber income is included in the necessary expenses that are used to calculate the Resident's real property income, business income, or timber income for the year in which the day of the loss falls.

災害又は盗難若しくは横領により居住者の有する山林について生じた損失の金額（保険金、損害賠償金その他これらに類するものにより補てんされる部分の金額を除く。）は、その者のその損失の生じた日の属する年分の事業所得の金額又は山林所得の金額の計算上、必要経費に算入する。

A loss due to Disaster, robbery, or misappropriation involving forested land owned by a Resident (other than any part of the loss covered by insurance benefits, compensation for damage, or anything similar to these) is included in the necessary expenses that are used to calculate the Resident's business income or timber income for the year in which the day of the loss falls.

居住者の不動産所得若しくは雑所得を生ずべき業務の用に供され又はこれらの所得の基因となる資産（山林及び第六十二条第一項（生活に通常必要でない資産の災害による損失）に規定する資産を除く。）の損失の金額（保険金、損害賠償金その他これらに類するものにより補てんされる部分の金額、資産の譲渡により又はこれに関連して生じたもの及び第一項若しくは第二項又は第七十二条第一項（雑損控除）に規定するものを除く。）は、それぞれ、その者のその損失の生じた日の属する年分の不動産所得の金額又は雑所得の金額（この項の規定を適用しないで計算したこれらの所得の金額とする。）を限度として、当該年分の不動産所得の金額又は雑所得の金額の計算上、必要経費に算入する。

A loss involving assets (other than forested land and assets prescribed in Article 62, paragraph (1) (Loss of Assets Not Ordinarily Necessary in Everyday Life, Due to Disaster)) used in the business operations of a Resident which are meant to generate real property income or miscellaneous income or are the basis of such income (other than any part of the loss covered by insurance benefits, compensation for damage, or anything similar to these; other than any loss due to or related to the transfer of an asset; and other than any loss prescribed in paragraph (1) or paragraph (2) or Article 72, paragraph (1) (Casualty Loss Deduction)) is included in the necessary expenses that are used to calculate the Resident's real property income or miscellaneous income for the year in which the day of the loss falls, up to the amount of the real property income or miscellaneous income for the year (meaning the amount of real property income or miscellaneous income for the year as calculated without applying the provisions of this paragraph).

第一項及び前二項に規定する損失の金額の計算に関し必要な事項は、政令で定める。

Cabinet Order provides for the necessary particulars concerning the calculation of the loss prescribed in paragraph (1) and the preceding two paragraphs.