PURPOSE: To prevent the release of raw gas by interposing in a discharge circuit a normally-opened switch which is closed as a manual actuator is brought to its ignition position and is opened at its open position, and by connecting a resistor parallelly with said normally-opened switch.

CONSTITUTION: Although an actuator 5 is returned to its open position and a normally-opened switch 18 is opened, the residual electrical load in a condenser 13 continues to be discharged via a resistor 19. Since no electrical load is left in the condencer 13 at the time of extinguishing, a charging electric current which is great enough flows from a power source 15 to a solenoid 3a. Therefore, such charging electric current cancels the thermoelectromotive current of a thermocouple 12 flowing to an electromagnetic safety valve 3 due to the residual heat to cause the electric current flowing to the solenoid 3a to become less than the release current. As a resutl, the electromagnetic safety valve 3 is closed instantly. In this manner, even when an ignition button 5a is pressed within a short time to close an ignition switch 21 while the manual actuator 5 is held at the open position, the release of gas from a unit 1 can be prevented.