The embodiments of the present disclosure provide a user device, which includes a main body part, a movable part electrically connected with the main body part, and a switching control unit and a rotation driver unit for co-axially connecting the main body part with the movable part. The switching control unit is used for eliminating a friction that enables the main body part to be fixed relative to the movable part fixed to turn on a rotation mode of the movable part. The rotation driver unit is used for applying a pre-pressing elastic force to the movable part when the switching control unit turns on the rotation mode of the movable part, so as to enable the movable part to automatically rotate relative to the main body part. The pre-pressing elastic force is less than the friction.