To provide a variable displacement swash plate clutchless compressor which can facilitate sealing management in respect to external air, suppress generation of noises, and improve reliability.

A check valve 30 is arranged on the way of a discharge passage 39 for introducing cooling medium gas in a discharge chamber 12 to a discharge port 1a. The discharge passage 39 is interrupted by the check valve 30, when pressure difference from a crank chamber 8 is a prescribed value or lower. Outflow of the cooling medium gas is therefore prevented from the discharge port 1a to a condenser 84, so that the cooling medium gas is internally circulated. It is thus unnecessary to attach a mechanism to a shaft 5 for internally circulating the cooling medium gas. Valve opening caused by rise of rotational speed is effectively prevented by adopting the check valve. In addition, burrs of a housing hole is not caught by the valve due to the fact that a seat portion is not a side surface of the housing hole but its end face.