A dual capacity compressor that prevents relative movement from taking place between certain components is provided. The dual capacity compressor includes a power generating part having a reversible motor and a crank shaft inserted in the motor, and a compression part having a cylinder, a piston and a connecting rod. A crank pin is provided in an upper part of the crank shaft, eccentric from an axis of the crank shaft, and an eccentric sleeve is rotatably fitted between the crank pin and an end of the connecting rod. A key member is held at least a part of the eccentric sleeve, and held at a particular portion of at the eccentric sleeve during operation so as to positively latch the eccentric sleeve with the crank pin in both directions rotation of the motor.