Labor Standards Act Article 57

Workers' years of service shall be limited to years of employment by the same business entity. In determining the years of service of a worker who is transferred to another business entity owned by the same employer, and in determining accumulated service years recognized by a new employer on a continued basis under Article 20 of the Act, the years of service at the different business entities shall be combined for calculation purposes.
中文原文 勞動基準法第57條
勞工工作年資以服務同一事業者為限。
但受同一雇主調動之工作年資,及依第二十條規定應由新雇主繼續予以承認之年資,應予併計。

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