Labor Pension Act Article 16

An employer shall contribute to the labor pension of an employee from the first date of employment to the date that the employee resigns; however, if an employee chooses to be covered by the pension system in the Act from the date of its enforcement, his/her contribution shall be made from the date they decide to be covered by the pension system in the Act until their date of resignation.
中文原文 勞工退休金條例第16條
勞工退休金自勞工到職之日起提繳至離職當日止。
但選擇自本條例施行之日起適用本條例之退休金制度者,其提繳自選擇適用本條例之退休金制度之日起至離職當日止。

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