Constitution of the Republic of China (Taiwan) Article 49

In case the office of the President should become vacant, the Vice President shall succeed until the expiration of the original presidential term. In case the office of both the President and the Vice President should become vacant, the President of the Executive Yuan shall act for the President; and, in accordance with the provisions of Article 30 of this Constitution, an extraordinary session of the National Assembly shall be convoked for the election of a new President and a new Vice President, who shall hold office until the completion of the term left unfinished by the preceding President. In case the President should be unable to attend to office due to any cause, the Vice President shall act for the President. In case both the President and Vice President should be unable to attend to office, the President of the Executive Yuan shall act for the President.