Abstract: A switch device including a case which is provided with a through hole and has a built-in module, a cylindrical member which is attached to the through hole of the case and whose inner end portion protrudes inside the case and is held in the module and outer end portion protrudes outside the case, and an operation member including a shaft section which is arranged inside the cylindrical member in a manner to be slidable in an axial direction of the cylindrical member so as to operate the module and a head section which is provided on an outer end portion of the shaft section and covers and slidably holds the outer end portion of the cylindrical member.