PURPOSE: To prevent secondary accidents due to the occurrence of an earthquake by constituting control means such that as the occurrence of an earthquake is detected by a seismoscopic sensor, a fuel pump is stopped.

CONSTITUTION: A seismoscopic sensor 62 for detecting an earthquake is provided in a hot air supply unit S, and a detection signal is input into control means 57. More specifically, a seismoscopic relay adapted to be opened and closed by a detection signal from the seismoscopic sensor 62 has its normally closed contact connected to a emergency stop switch 59 in series. Connected to a normally open contact side of the seismoscopic relay is a lamp 64 for indicating a stopping state due to an earthquake. When the normally closed contact of the seismoscopic relay is opened by a detection signal from the seismoscopic sensor 62, an electric current for a power circuit for a control unit is shut off. Then an electric current for a safety valve 53 biased toward a closed side and a fuel pump 52 is shut off, so that the safety valve 53 is closed and driving of the fuel pump 52 is stopped. Thus as an earthquake is detected by the seismoscopic sensor 62, the control means 57 closes the safety valve 53 and stops the fuel pump 52.