PURPOSE: To simplify the structure in comparison with a conventional device in the burner wherein gas and liquid are utilized as a heat source, by employing only one pipe which is connected to a burning chamber in the burner main body.

CONSTITUTION: One end of an oil feeding pipe 4 is connected to the burning chamber 3, and the other end is connected to an oil supply source via an oil flow regulating device 5. A gas feeding pipe 6 is branched and connected to said oil feeding pipe 4. An inverted U part 7 is provided in said gas feeding pipe 6. The height of the U part 7 is higher than the height of the head in the oil regulating device 5 by H. Thus the oil does not enter into the gas feeding pipe 6. The gas feeding pipe 6 is connected to a gas supply source 1 via a solenoid controlled valve 8 and a governor 9. A burning blower 10 is provided in the burner main body 1, a forced air is mixed with evaporated fuel in an evaporating device 11 in the burning chamber 3, and the mixture is burned in said burning chamber.