The Administrative Court Organization Act Article 4
In a collegial trial, the Division-Chief Judge shall be the Presiding Judge; in the absence of the Division-Chief Judge, the most senior judge of the same division, or the eldest of the judges of the same seniority, shall act as the Presiding Judge.In a single judge trial, the said judge shall assume the duty and authority of the presiding judge.
中文原文 行政法院組織法第4條
合議審判，以庭長充審判長；無庭長或庭長有事故時，以同庭法官中資深者充之，資同以年長者充之。
獨任審判，即以該法官行審判長之職權。
獨任審判，即以該法官行審判長之職權。