Police Power Exercise Act Article 18

When the data legally collected by the police is no longer effective for the police to accomplish their mission, it shall be cancelled or destroyed unless the cancellation or destruction of the data will endanger an interest of the collection target that merits protection.Data that shall be cancelled or destroyed shall not be transferred or used in ways that are harmful to the collection target.Collected data shall be cancelled or destroyed within five years after it was created, unless otherwise specified by the law.
中文原文 警察職權行使法第18條
警察依法取得之資料對警察之完成任務不再有幫助者,應予以註銷或銷毀。
但資料之註銷或銷毀將危及被蒐集對象值得保護之利益者,不在此限。
應註銷或銷毀之資料,不得傳遞,亦不得為不利於被蒐集對象之利用。
除法律另有特別規定者外,所蒐集之資料,至遲應於資料製作完成時起五年內註銷或銷毀之。

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