Ministry of Education’s Regulations Governing the Establishment of the National Professorship Article 5

The term of each National Chair Professorship is three years. If it is necessary for a National Chair Professorship to be extended beyond the end of this term, the procedures set out in the provisions of Article 3 shall be conducted before the term ends.Any person who has served two terms as a National Chair Professor shall become an honorary life-time National Chair Professor, without participating in any further recommendation or selection process.
中文原文 教育部設置國家講座辦法第5條
國家講座之設置期限為三年。
期滿後,有繼續設置之必要者,應於期限屆滿前依第三條規定程序辦理。
曾獲二屆國家講座主持人者,即成為終生榮譽,不再接受推薦或遴選。

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