Abstract: An illumination type push button switch wherein a switch mechanism and an illuminant such as a light emitting diode are provided interiorly of a casing, a pair of external terminals adapted to supply power to the illuminant to light the same are supported on a base plate detatchably supported on said casing. An electronic circuit is formed on the base plate so that the circuit may be interposed in the electric connection between the illuminant and the external terminals, thereby rendering miniaturization of the switch possible and facilitating handling of the same.