PURPOSE: To enable an amount of compressed discharged refrigerant to be nil and dispense with a clutch by providing a swash plate operating mechanism which forcibly inclines a drive swash plate connected to a drive shaft at a variable angle of inclination and approximately perpendicularly to the drive shaft.

CONSTITUTION: A wabble plate 16 is slidably mounted on a drive swash plate 13 having variable angles of inclination to reciprocate a piston 23 connected to the unrotatable wabble plate 16 through a piston rod 22 by the rotation of the drive swash plate 13 for discharging refrigerant. In such a compressor, the drive swash plate 13 is additionally provided with a swash plate operating mechanism 52 which is constituted to withdraw axially rightward an operating rod 53 by turning on an electromagnet 54 so that the drive swash plate 13 is erected on a drive shaft 11. And an amount of refrigerant compressed and discharged by said compressor is made to nil by the excitation of said electromagnet 54 to dispense with a clutch provided in the compressor drive system.