To provide the structure of an operation part, which enables an operational position to be retained and enough waterproofness to be obtained without hampering miniaturization, thinning, and the like of the equipment.

An operational member 14 is inserted into a through hole 11a of a body 11, and an external operational member 18 is fitted into a recessed part 11b. On the inner surface of the external operational member 18, an inner surface plate 19 is mounted, which is abutted on the outer end 14b of the operational member 14. When the external operational member 18 is moved in the direction perpendicular to the face of the shown figure, the operational member 14 is pressed in by the inner surface plate 19.