A capacity varying rotary compressor is provided. The compressor includes a casing that maintains a discharge pressure state, a motor installed in the casing that generates a driving force, one or more cylinder assemblies provided in the casing to compress refrigerant with a rolling piston and a vane. The rolling piston is eccentrically coupled to a rotation shaft of the motor to perform a linear motion, and a vane restricting device restricts or releases the vane from the rolling piston according to a difference in pressures applied to the vane. A structure of the compressor may be simplified, resulting in reduced production costs and enhanced productivity. Further, as the vane is restricted by a pressure differential, reliability may be enhanced.