PURPOSE: To execute the sensitivity control and mode setting or the like of a detecting switch without contacting by providing a setting means, which sets the function of the detecting switch by receiving a signal from the detecting switch, at the detecting switch.

CONSTITUTION: The setting signal is transmitted without contacting from a setting device 1A, which is equipped with a key input part 11 and a signal transmitting means, to the side of a detecting switch 2A. When the signal is received, the detecting switch 2A transmits it from a transmission/reception coil 31 through a demodulation circuit 32 to a control part 34. When this signal is normally received, the control part 3 sets a constant to a constant setting part 39. Then, a normal end signal is transmitted to show the normal reception of the signal and the setting of the constant. On the other hand, when the normal end signal is obtained from the side of the detecting switch 2A, on the side of the setting device 1A, a normal end state is displayed and a processing is finished. Thus, the sensitivity, etc., of the detecting switch 2A can be set from the outside without contacting.