To favourably prevent erroneous display of emission of a light emitting diode by high frequency noise as an element by preventing the high frequency noise from working on the light emitting diode by a small capacitor of low rated voltage without being influenced by specification voltage of solenoid.

Resistors 16A, 16B to limit an electric current and light emitting diodes 17A, 17B to emit light by electrification to coils 5A, 5B are connected to each other in parallel between both ends of the coils 5A, 5B of solenoid, and capacitors 18A, 18B are connected to each other in parallel between both ends of the light emitting diodes 17A, 17B. Consequently, in the case when high frequency noise from outside is superimposed on electric wires 11A,..., 11C from a direct current electric power source P, the high frequency noise passes through the capacitors 18A, 18B, and the light emitting diodes 17A, 17B do not emit light. The capacitors 18A, 18B can be low in rated voltage and small as low voltage works since the electric current is limited by the resistors 16A, 16B.