PURPOSE: To provide a swash plate type compressor with a small-sized and hard mechanism having a simple structure.

CONSTITUTION: A plurality of cylinders 13a... are bored in a cylinder block 2, a plurality of pistons 30a... are inserted thereto, and these pistons are reciprocated by a swash plate 27 mounted on a rotating shaft 24. Passages 54, 36 for connecting a swash plate chamber 23 in which the swash plate is received to intake chambers 10, 11, 16 (independent, respectively) of the respective cylinders have control pistons 34, 46 inserted to control cylinders 33, 45 to open and close them, and the control pressures to be supplied to the control pressure chambers 38, 51 are switched by a control valve 39, whereby the control pistons 34, 46 are moved to select an inlet chamber to supply the fluid from the swash plate chamber 23, and the number of the cylinders conducting effective compression work is changed, whereby the discharge capacity is changed in multistage.