To enable the opening of a valve of a flow passage without electrifying so as to reduce the power consumption by providing a valve moving means for pushing the part of a plunger side so as to move a valve body of a plunger of a self-holding type solenoid valve to the valve opening direction for valve opening.

At the time of switching the operation from the valve closing condition that a valve hole 30 is sealed by a valve element 32 of a self-holding type solenoid valve 5 to the valve opening condition, a solenoid 34 is electrified so that a core 33 has a polarity for attracting a plunger 31, and the plunger 31 is moved toward the core 33, resisting a spring 36, and the valve element 32 is separated from the valve hole 30 so as to open a main gas flow passage 7. In the case here an operating member 26 of a switching operation unit 24 is pushed, a pushing plate 41 of a needle operating member 40 is pushed by a pushing member 29 so as to open the throttle of a needle 6, and at the same time, a tip of a rod member 38 is pushed through the pushing plate 41 of the needle operating member 40, and the valve element 32 is moved right so as to open the valve hole 30 of the main gas flow passage 7.