To safely vaporize a liquid of a liquefied gas in a small space by means of small energy in a liquefied gas vaporizing device and to adjust combustion gas during combustion.

Solenoid valves 216, 217A, B and an ignition transformer 333, which intervene in a fuel gas flow passage for opening the fuel gas flow passage only when conducting so as to feed fuel gas to a burner 112, are provided within an internal pressure container 209 which can be pressurized to pressures in excess of atmospheric pressure, and air not containing combustible gas is fed by a blower 206 to the burner 112 via the internal pressure container 209. A portion of the fuel gas flow passage downstream of the solenoid valves is positioned externally of the internal pressure container 209 and fuel gas regulators 218A, B and a gas pressure detecting port 219 are positioned in that portion of the fuel gas flow passage. Further, a control board 319 is provided which causes the solenoid valves 216, 217A, B and the ignition transformer 333 to conduct after the elapse of a predetermined time since the internal pressure in the internal pressure container 209 has become equal to or greater than a predetermined pressure exceeding the atmospheric pressure.