Abstract: There is disclosed a hot gas generator comprising a compressor for supplying compressed air to a combustion chamber, a gas turbine driven by hot gas flowing from the combustion chamber and operatively connected to the compressor by means of a common rotary shaft, a blower for starting the compressor, an air pressure sensor for detecting an inlet pressure of air supplied to the compressor, a flame monitoring sensor for confirming ignition, a valve for controlling fuel gas supply to the combustion chamber, and a control mechanism. The control mechanism is operable to open the valve to a certain extent and actuate an ignition device at the same time upon a predetermined time lapse after blower actuation, to stop the ignition device and open the valve at a predetermined speed at the same time in response to an ignition confirmation signal from the flame monitoring sensor, and to stop the blower in response to a signal from the air pressure sensor indicating that the generator is in self-sustaining operation.