PURPOSE: To eliminate the possibility of the lubrication failure of a sealing device which could be anticipated when a discharge capacity decreases by providing a bypass line through which a fluid containing lubricating oil is guided to a sealed chamber while the area of an opening communicated with an intake chamber by a spool moving inside a housing is gradually varied.

CONSTITUTION: When a compressor 100 takes a minimum discharge capacity, the openings 44a, 44b of each of e.g. five rear intake ducts 44 can be blocked by the diameter-enlarged portion 68a of a spool 68 with a time difference, and a bypass line 100b passing through a sealed chamber 76 is provided between front and rear intake chambers 32, 34. When a control piston 40 starts to move rightwards from its left end in such a way as to decrease the discharge capacity, closing of the opening 44b is immediately started and then the opening 44a is closed later. Therefore, even if a front operating chamber 30 becomes decompressed, part of refrigerant being supplied to the rear intake chamber 34 is allowed to gradually pass through both the intake chamber 34 and the sealed chamber 76, and lubricating oil contained therein can be supplied to a sealing device 52.