法令翻訳 http://www.japaneselawtranslat...ky=&page=2

(非居住者の給与又は報酬で源泉徴収が行われたものとみなされるもの)
第三百三十四条  法第二百十五条（非居住者の人的役務の提供による給与等に係る源泉徴収の特例）の規定により所得税の徴収が行われたものとみなされる給与又は報酬の金額は、法第百六十一条第二号（国内源泉所得）に規定する事業を国内において行う者の当該国内において行う事業につき支払を受けた同号に掲げる対価の総額が当該国内において行う事業のために人的役務の提供をする各非居住者に対しその人的役務の提供につき支払うべき同条第八号イ又はハに掲げる給与又は報酬の金額の合計額に満たなかつた場合には、当該対価の総額に、当該合計額のうちに当該各非居住者に対し支払うべき当該給与又は報酬の金額の占める割合を乗じて計算した金額とする。

Salaries or Remuneration of Nonresidents Deemed to Be Subject to Withholding
Article 334  The amount of salaries or remuneration for which income tax is deemed to have been collected pursuant to the provisions of Article 215 (Special Provisions on Withholding on Salaries, etc. from the Provision of Personal Services by Nonresidents) of the Act is to, if the total amount of the consideration listed in Article 161, item (ii) (Domestic Source Income) of the Act that a person who conducts a business prescribed in Article 161, item (ii) of the Act in Japan has received with regard to that business conducted in Japan does not reach the sum of the amounts of salaries or remuneration listed in Article 161, item (viii), (a) or (c) of the Act to be paid to individual nonresidents who provide personal services for that business conducted in Japan with regard to their provision of personal services, be the amount calculated by multiplying the total amount of consideration by the ratio of the amount of salaries or remuneration to be paid to the respective nonresident to the total amount of the consideration.