PURPOSE: To restrict a useless consumption of fuel gas by a method wherein a burner nozzle and a main body of a burner valve are lifted up, and then a desired measuring space of predetermined capacity is formed between a first valve seat and a valve part and also between a second valve seat and the valve part.

CONSTITUTION: A burner nozzle 3 is lifted up in cooperation with an operation of an operating lever 7 and a main body 12 of a burner valve is lifted in integral with the burner nozzle. A second valve seat 17 is press contacted against a second valve part 20 under a lifting-up of the main body 12 of the burner valve so as to close the second valve part 20 and at the same time the first valve part 19 is moved away from a first valve seat 24, so that fuel gas contained in the measuring space including a gas accumulation space 25 is injected out of a nozzle hole 23 and ignited. Since a supplying of fuel gas from a fuel tank to the measuring space is shut off due to the press contact between the second valve part 20 and the second valve seat 17, so that the flame is automatically extinguished by consumption of gas within the measuring space. With such an arrangement as above, it is possible to restrict useless consumption of the fuel gas.