A spool operation failure due to foreign matter contamination is prevented. A variable displacement compressor 100 includes a first control valve 300 controlling the opening degree of a supply passage 145, a check valve 350, a second control valve 400 controlling the opening degree of a discharge passage 146, and a back-pressure relief passage 147. The second control valve 400 includes a back pressure chamber 410 communicating with an intermediate supply passage 145b1, a valve chamber 420 to which a valve hole 103d and a discharge hole 431a are open and that constitutes a part of the discharge passage 146, a partition member 430 partitioning into the back pressure chamber 410 and the valve chamber 420, and a spool 440 extending through a through hole 432a formed in the partition member 430. The spool 440 has a pressure receiving portion 441 disposed in the back pressure chamber 410, a valve portion 442 disposed in the valve chamber 420, and a shaft portion 443. The spool 440 is supported in a manner slidable in the opening and closing directions on the partition member 430 by arranging the spool valve 440a, constituted by the valve portion 442 and the shaft portion 443, to be in contact with the partition member 430.