Disclosed is a variable capacity type rotary compressor, in which a refrigerant sucked via one suction pipe can be alternately sucked into each compression space via a communication passage between a plurality of cylinders so as to reduce the number of components and the number of assembly processes, thereby remarkably reducing a fabricating cost, a refrigerant within an idling cylinder can be prevented from flowing back into another cylinder so as to improve the performance of the compressor, a welding space can be ensured when connecting connection pipes so as to realize a welding automation, thereby further reducing the fabricating cost, and a mode switching valve can be stably fixed to an appropriate position so as to attenuate noise due to vibration of the compressor.