To detect a contact with an exterior without mounting a switch on the exterior.

A head switch 41 comprises a support member 111 with contact type switches: a first switch 110a and a second switch 110b, and a switch pressing member 112 consisting of a nearly board-shaped switch presser part 113 that moves integrally with the exterior and a presser part 114, wherein the parts 113, 114 are integrated with each other. The presser part 114 consists of first and second projections 114a and 114b, projecting from the rear surface 113a of the switch presser part 113, which are located above the first switch 110 and the second switch 110b, respectively. The head switch 41 also has elastic members 115a and 115b for keeping the first and second projections 114a and 114b of the presser part 114 and the first and second switches 110a and 110b in the non-contact state by the elastic force.