A multi-stage rotary compressor comprises: a casing having a sealed space therein; a driving unit installed in the casing, for generating a driving force; a first compression unit and a second compression unit for receiving the driving force from the driving unit and compressing a refrigerant; and a connection unit for connecting the first and second compression units and guiding the refrigerant discharged from the second compression unit to be sucked directly in the first compression unit and then re-compressed, by which it is possible to vary capacity, even using every plurality of compression units, and to obtain power saving effect suitable for a saving mode.