PURPOSE: To reduce CO, THC and soot or the like and make a smooth adjustment of fire power by a method wherein a heat is smoothly guided to a heat exchanger through a closed-loop type thermal conductor.

CONSTITUTION: Heat to be fed from the storing part 3 storing a wick 1 under a thermal conduction is guided to a heat exchanger 11 with a thermal conductor 9. The fuel is evaporated by an amount corresponding to a difference between the amount of radiation and a calorie to be fed to the wick 1 and then the ignition of the fuel is continued. In order to adjust a fire power, the wick 1 is descended and then an exposed area is decreased. Then, since the amount of evaporation of the fuel is decreased, the area of ignition is moved to a part near the wick 1 in the ignition chamber 7 to increase the temperature around the wick. However, since multi-layered metal material is arranged between the storing part 3 and the pipe 9, the heat in the storing part 3 is smoothly conducted to the thermal conduction plate 9 and radiated at the radiator part 11, its temperature is not increased. With this arrangement, it is possible to expand a range of adjustment of the fire power and make a smooth adjustment of the fire power.