PURPOSE: To easily secure waterproofness by making the body of a first switch handle slidable in the axial direction, and a second switch handle slide in the circumferential direction and consisting a strength change-over switch operated by a second switch handle of a reed switch.

CONSTITUTION: A first switch handle 2 to be used as a switch for on-off of power and a second switch handle 3 for a strength changeover switch are provided. The first switch handle 2 is installed such that it is slidable in the axial direction of a body, and the second switch handle 3 is installed such that it is slidable in the circumferential direction of the body. A switch which can be changed by the first switch handle 2 is a contact switch, and the strength change-over switch is formed of a reed switch. There are a few possibility, therefore, that strength may be carelessly changed over, and the strength change- over switch operated by the second switch handle 3 is constituted of a reed switch. Thereby, waterproofness can be easily secured.