PURPOSE: To make an output variation ever so easy, by regulating the number of combustion times and a speed of rotation in a compression fan and an output turbine by means of rotation in a combustion chamber rotor.

CONSTITUTION: A turbine shaft 9 is connected to a combustion chamber rotor 2 by a turbine shaft gear 10, while compressed gas out of a compression fan 1 is inhaled in a combustion chamber 6 of the combustion chamber rotor 2 from a suction port 7 and, after being ignited by a spark plug, led into an output turbine 3 from an exhaust port 8. A difference between output by the output turbine 3 and such force as being necessary to rotate the combustion fan 1 and the combustion chamber rotor 2 is taken out of a driving shaft 5. Thus, since the number of combustion times and a speed of rotation in the combustion fan and the output turbine are regulated by rotation in the combustion chamber rotor, an output variation is attainable in an easy manner.