An electronic device including a housing, a cover plate, and a button is provided. The cover plate is separably disposed on the housing and corresponds to an opening on the housing. A groove is formed on an edge of the cover plate. The button pivotally connects to an edge of the housing which encompasses the opening. The button can rotate on a housing plate of the housing and corresponds to the position of the groove. The button is behind the edge of the housing while the button is in a release position; a portion of the button extends out and into the groove of the cover plate while the button rotates to a lock position.