PURPOSE: To eliminate leak and facilitate the temperature control of oil by a method wherein an auxiliary valve driving means is operated after a main valve is closed fully so that the auxiliary valve closes an auxiliary passageway instantaneously.

CONSTITUTION: When a heat sensitive pipe 47 detects high temperature, a bellows 42 is expanded, a spring receiver 36 is elevated, a lever 20 is turned clockwise, a main valve 18 is descended by the energizing force of a coil spring 22, a gap between the main valve 18 and a valve seat 14 is reduced and the flow amount of gas is reduced. A distance between a supporting shaft 34 and the abutting point of a rod 17 is larger than a distance between the supporting shaft 34 and the operating point of the bellows, therefore, the main valve 18 is moved up-and-down in accordance with the slight expansion of the bellows 42. When the high temperature condition is still maintained, the main valve 18 is abutted against the valve seat 14 and the flow of gas is intercepted, but the auxiliary valve 26 is still opened, therefore, a part of the gas flows out of a small hole 25. When the temperature becomes higher further, the lower surface of the tip end of the lever 24 turns a microswitch 29 ON, the operating pin 28 of a solenoid 27 pushes the auxiliary valve 26 and the small hole 25 is closed whereby the flow of gas in an auxiliary passageway is intercepted instantaneously.