A first swash plate 18 is coupled to a drive shaft 16 to be rotatable integrally with the drive shaft 16. Single head pistons 23 are coupled to the first swash plate 18 via shoes 25A, 25B. Rotation of the drive shaft 16 rotates the first swash plate 18, which causes the pistons 23 to reciprocate and compress refrigerant gas. The first swash plate 18 supports an annular second swash plate 51 to be rotatable relative to the first swash plate 18 via a ball bearing 52. The second swash plate 51 is arranged between the first swash plate 18 and the shoes 25B that receive a compressive load to be slidable with respect to the first swash plate 18 and the shoes 25B. Therefore, the first swash plate reliably slides with respect to the second swash plate.