A switch device (10, 10a, 300) comprising: a tubular case (18, 308); a circuit board (14, 304) disposed in the case (18, 308); a control button (34, 318) disposed for movement along longitudinal directions of the case (18, 308), the control button (34, 318) being actuated by pressing from outside of the switch device (10, 10a, 300); a switch unit mounted on the circuit board (14, 304), the switch unit being actuated in response to rearward movement of the control button (34, 318) by pressing; a coil antenna (194, 328), for emitting a radio wave for energizing an external portable device; wherein the coil antenna (194, 328) is disposed rearwardly of the control button (34, 318) and has an outside diameter which is the same as the outside diameter of the control button (34, 318), a slider (22, 310) disposed in the case (18, 308) for sliding movement along the longitudinal directions while allowing the switch unit to be actuated, the control button (34, 318) being disposed on a front end of the slider (22, 310), characterized in that the circuit board (14, 304) has a mounting surface facing forwardly; and the switch unit has a contact assembly (112, 114) disposed on the mounting surface, the contact assembly (112, 114) being elastically deformable, further comprising: a plurality of light-emitting elements (86, 88, 90, 92, 94) mounted on the mounting surface of the circuit board (14, 304), for illuminating the control button (34, 318), wherein the slider (22, 310) has a plurality of light guides (24, 26, 28, 312, 314, 316) for guiding light emitted from the light-emitting elements (86, 88, 90, 92, 94) to the control button (34, 318). a tubular case (18, 308); a circuit board (14, 304) disposed in the case (18, 308); a control button (34, 318) disposed for movement along longitudinal directions of the case (18, 308), the control button (34, 318) being actuated by pressing from outside of the switch device (10, 10a, 300); a switch unit mounted on the circuit board (14, 304), the switch unit being actuated in response to rearward movement of the control button (34, 318) by pressing; a coil antenna (194, 328), for emitting a radio wave for energizing an external portable device; wherein the coil antenna (194, 328) is disposed rearwardly of the control button (34, 318) and has an outside diameter which is the same as the outside diameter of the control button (34, 318), a slider (22, 310) disposed in the case (18, 308) for sliding movement along the longitudinal directions while allowing the switch unit to be actuated, the control button (34, 318) being disposed on a front end of the slider (22, 310), characterized in that the circuit board (14, 304) has a mounting surface facing forwardly; and the switch unit has a contact assembly (112, 114) disposed on the mounting surface, the contact assembly (112, 114) being elastically deformable, further comprising: a plurality of light-emitting elements (86, 88, 90, 92, 94) mounted on the mounting surface of the circuit board (14, 304), for illuminating the control button (34, 318), wherein the slider (22, 310) has a plurality of light guides (24, 26, 28, 312, 314, 316) for guiding light emitted from the light-emitting elements (86, 88, 90, 92, 94) to the control button (34, 318). a plurality of light-emitting elements (86, 88, 90, 92, 94) mounted on the mounting surface of the circuit board (14, 304), for illuminating the control button (34, 318), wherein the slider (22, 310) has a plurality of light guides (24, 26, 28, 312, 314, 316) for guiding light emitted from the light-emitting elements (86, 88, 90, 92, 94) to the control button (34, 318).