The present disclosure relates to a hand-held electric device with changeable head, includes an electrical hand-held part and a head. The electrical hand-held part has a hand-held body, an inner casing and an outer casing, the hand-held body has a first sealing ring located at the front end thereof, the inner casing is mounted at the front end of the hand-held body and the outer wall of is provided with a second sealing ring. The outer casing slides back and forth along the axis of the inner casing at the outside of the inner casing. The head includes a head body and an assembling and matching part disposed at the rear end of the head body, the assembly mating part is detachably assembled on the inner side of the inner casing, and the assembling and matching part is provided with a third sealing ring.