Abstract: A switch device of reduced thickness is provided for use in motor vehicles or the like in which a switching element in a casing is operated with an operating knob. Such a switch device can be assembled with ease and is stable in the operation of the switching element. Such a switch device may be installed both on the right side and on the left side, while employing one and the same casing, and is therefore low in manufacturing cost. In the switch device, a switching element is provided inside a casing, and is operated with an operating knob provided on the outer surface of the casing. The switching element is secured to the back of the circuit board by soldering its fixing terminals on the side of the surface of the circuit board, and a driven part of the switching element, which is operated with the operating knob, is stuck out on the side of the surface of the circuit board through an opening formed in the latter.