A variable displacement compressor comprising a displacement control valve disposed somewhere in a discharge pressure supply passageway capable of communicating with a crank chamber from a discharge chamber, and a fixed orifice disposed somewhere in a pressure relief passageway communicating with a suction chamber from the crank chamber, the displacement control valve being controlled in opening/closing operation to adjust a pressure in the crank chamber to control a piston stroke, wherein a part of the discharge pressure supply passageway and a part of the pressure relief passageway are formed as a common passageway communicating with a crank chamber end. Variable displacement control at a high reliability is possible with no foreign matter accumulation in the displacement control passageway, and the processing of a cylinder block is simplified.