A variable capacity rotary compressor to reduce an electric power loss thereof and includes a drive unit to generate a rotating force, a rotating shaft connected to the drive unit to rotate thereby, and a compressing cylinder through which the rotating shaft passes. A compressing chamber is defined in the compressing cylinder to compress refrigerant therein, with a first refrigerant inlet port provided at the compressing chamber to introduce the refrigerant into the compressing chamber. A capacity control unit controls an operation of the rotary compressor, so that the rotary compressor performs one of a normal-mode operation wherein the first refrigerant inlet port is maintained at an open state thereof, and the variable capacity-mode operation wherein the first refrigerant inlet port is periodically opened and closed.