A variable displacement swash plate type compressor operable with reduced vibration and noise and, hence, suitable for use in automotive air-conditioning refrigeration cycle has a main shaft adapted to be driven by a driving power source; a drive plate fixed to the main shaft; a swash plate main part tiltably engaging through an engaging portion with the drive plate so as to be tiltable with respect to the axis of the main shaft and to make a precessional rotation in accordance with the rotation of the main shaft; a piston support rotatably carried by the swash plate main part so as to make a precessional rotation together with the swash plate main part; pistons having one ends engaging with the piston support so as to reciprocatingly move in respective cylinders in accordance with the precessional rotation of the swash plate main part; and a mechanism for causing a change in the angle of tilt of the swash plate main part with respect to the axis of the main shaft so as to effect a control of displacement. The swash plate main part is provided with a balancing portion which cancels an unbalance of mass produced by the engaging portion at a predetermined angle of tilt of the swash plate so as to locate at least the gravity center of the swash plate main part on the axis of the main shaft.