Collective Agreement Act Article 28

When a collective agreement is concluded in the form of fixed-term, its duration may not exceed three years; if the duration exceeds three years, it shall be shortened to three years.
中文原文 團體協約法第28條
團體協約為定期者,其期限不得超過三年;超過三年者,縮短為三年。

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