Labor Standards Act Article 32-1

(Ⅰ)When an employer extends the work according to Paragraphs 1 and 2 of Article 32 or requests the worker to perform work on rest days as prescribed in Article 36, the employer shall calculate the hours of compensatory leave based on the hours of work performed, as the worker chooses to take compensatory leave with the consent of the employer.(Ⅱ)The period of the compensatory leave referred to in the preceding Paragraph shall be agreed on by the employer and the worker; should compensatory leaves not be used by workers upon the expiration of the compensatory leaves or the termination of the contracts, wages shall be paid based on the day when working hours are extended or the rest day when the worker performs work; employers failing to pay the said wages will be punished for violating the provisions of Article 24.
中文原文 勞動基準法第32-1條
雇主依第三十二條第一項及第二項規定使勞工延長工作時間,或使勞工於第三十六條所定休息日工作後,依勞工意願選擇補休並經雇主同意者,應依勞工工作之時數計算補休時數。
前項之補休,其補休期限由勞雇雙方協商;補休期限屆期或契約終止未補休之時數,應依延長工作時間或休息日工作當日之工資計算標準發給工資;未發給工資者,依違反第二十四條規定論處。

English translation for reference only; the Chinese text prevails. Not legal advice.