A brush head is provided on the front surface at a distal-end-side part of a neck of a replaceable brush. A fitting shaft portion is provided on a planting base of the brush head so as to protrude rearward and penetrate through a support wall portion of the neck. A shaft hole is formed at a rotation center of a brush head body of the brush head so as to extend frontward from a rear surface of the brush head body. The neck has ahead support shaft mounted to the shaft hole so as to rotatably support the brush head. A front end of the head support shaft is located frontward of a rear surface of the planting base, and power from the driving portion is transmitted to a rear part of the fitting shaft portion.
