A variable capacity rotary compressor, which is designed to make an internal pressure of a compression chamber, where an idle rotation is executed, be equal to an outlet side pressure of the rotary compressor, thus minimizing a rotating resistance. The compressor includes a housing partitioned into two compression chambers having different capacities by a partition plate. A rotating shaft rotates in the compression chambers. Two eccentric units are mounted to the rotating shaft to be placed in the compression chambers, and execute a compression rotation and an idle rotation according to a rotating direction of the rotating shaft. A pressure control unit functions to apply the pressure of the outlet side of the compressor to the compression chamber which executes the idle rotation. The pressure control unit includes a path control channel which is vertically provided through the partition plate to be placed at a position outside the compression chambers. Two valve seats are seated in opposite ends of the path control channel. A valve member is movably set in the path control channel. A communicating path is provided through the partition plate to make the outlet side communicate with the path control channel. Two inlet channels are provided at predetermined positions of the housing to make the path control channel communicate with the compression chambers.