PURPOSE: To make it possible to obtain a small-sized and lightweight drive section and to reduce noises and vibrations by a method wherein counter-weights capable of producing a couple of forces in the direction same as that of the couple of forces generating due to the centrifugal force of a swash plate are provided on an output shaft fixed to the swash plate.

CONSTITUTION: A Stirling engine 1 is provided with an operation piston 5 which reciprocates due to the isothermal expansion, compression and the isothermal change of an operation gas supplied to an expansion chamber 3 and a compression chamber 4 within a cylinder 2 and which is connected to a guide piston 7 through a rod 6. Further, the swash plate 7 is made to engage a central grooved section of the guide piston 7 and the output shaft 11 provided with a flywheel 10 is fixed to the central part of the swash plate 9. In this case, a first counter- weight 12 is attached to one end of the output shaft 11 and a second counter- weight 13 is attached to the flywheel 10 so that the couple of forces generates at the output shaft 11 in the direction in which the couple of forces due to the centrifugal force of the swash plate 9 generate.