A swing member is supported by a swing support member like a universal joint of a Hook's type such that it can swing in a state where it is prevented from rotating around a center line. In this manner, even if a shaft rotates at high speed, the swing member is surely prevented from rotating around the shaft. Therefore, it is possible to prevent a piston from excessively vibrating, hence to prevent large noises from being made, and to improve reliability and durability of a compressor when the compressor is operated at high speed.