A switch cover 50 is configured by having a first deformation portion 53 that is connectively provided at a flat surface portion 52a of a cylindrical portion 52 placed to surround a periphery of a switch portion 41, and deforms by an external stress, a second deformation portion 54 that is connectively provided at a curved surface portion 52b of the cylindrical portion 52, and deformed by the external stress, and a stress transmitting portion 55 that is connectively provided at the first and the second deformation portions 53, 54, and transmits a stress having a component in a perpendicular direction with respect to an outer surface of an operation portion main body 23 to the switch portion 41 when the first deformation portion 53 is deformed inward of the cylindrical portion 52 by the external stress.
