To lower exhaust temperature and improve environment during operation of an auxiliary power generating device by connecting special noise suppressors to an air inlet and a gas outlet during operation of the auxiliary power generating device in parking or provide a noise suppressor with a temperature lowering function for protecting sound absorbing material in an outlet side.

The noise suppressor is provided with a mobile vehicle 5, a vertically moving device 6 provided on the mobile vehicle 5, and a silencer 7 supported by the vertically moving device. The silencer is composed of a cylinder having a discharge opening 11b and a suction opening 11a to be connected to the outlet 3 from a turbine of the turbine type auxiliary power generating device for the aircraft. The cylinder is composed of metal-made inner and outer double cylinders 12 and 13, the heat resistant sound absorbing material 14 is filled between the inner and outer cylinders, and the inner cylinder 12 is composed of a punching metal having a multiplicity of sound absorbing holes. An outside air inducing part 16 taking in outside air by using fast exhaust gas from the turbine is provided in the cylinder, and outside air of the outside air inducing part is mixed with exhaust from the turbine outlet of the turbine type auxiliary power generating device for the aircraft.