PURPOSE: To attain excellent durability and to simplify an equipment without requiring a power supply, by turning on/off a relay with a signal from a transmitter comprising a piezoelectric element for attaining remote control.

CONSTITUTION: When a timer contact T1 is closed and the impulse voltage of an oscillator A is impressed to the gate of a thyristor D4, a relay L2 is operated, its contact L21 is opened, the operation of a relay L1 is stopped, its contact L13 is opened and the remote control is attained. Further, the power supply connection for the relay L2 and the thyristor D4 is delayed to the relay L1 by the timer T, because the operation of the contact L13 to the piezoelectric element of the oscillator A is ensured and the malfunction of the contact L13 is prevented due to noise produced in case of emergency because of impulse application to the piezoelectric element.