Disclosed is a compressor having a drive shaft in a crank chamber and a swash plate supported on the drive shaft for integral rotation therewith to drive a piston in a cylinder bore. The piston compresses gas sucked from a suction chamber into the cylinder bore and discharges the compressed gas to a discharge chamber and the amount of the discharged gas is variable between a minimum and maximum values based on variation of the inclined angle of the swash plate between a minimum and maximum values. The compressor comprises a passage for leading the gas into the crank chamber from the discharge chamber to alter the inclined angle of the swash plate, a valve for selectively opening and closing the passage to lead the gas into the crank chamber via the passage when the valve opens the passage, and a control apparatus for controlling the inclined angle of the swash plate, which operates in accordance with the operation of the valve to hold the swash plate at the minimum inclined angle when the valve means opens the passage.