Modulation type rotary compressor

A variable displacement type rotary compressor is provided to form a sealed vane chamber at a rear part of a second vane to supply suction/discharge pressure alternately, and form a side pressure path for connecting an inner space of a casing to a vane slot, thereby restraining a vane by pressure of the inner space of the casing in a power-saving mode. A variable displacement type rotary compressor includes a casing(10) filled with a predetermined amount of oil and kept in a discharge pressure state. At least a cylinder(41) is mounted in the casing and forms a vane chamber(41b) separated from an inner space of the casing together with a plurality of bearing plates. A vane(44) carries out straight reciprocation motion in contact with a rolling piston(43) in the cylinder for inhaling and compressing refrigerant together with the rolling piston. A valve unit connects the vane chamber to a suction part or a discharge part alternatively, and supplies suction pressure or discharge pressure to the vane chamber for contact or separation between the vane and the rolling piston. A vane restraining part such as a side pressure path(42c) guides refrigerant gas or oil in the casing to at least one of side surfaces of the vane in the axial direction, thereby restraining the vane.