A rotary compressor that has two compression capacities is provided. The rotary compressor includes a driving shaft having an eccentric portion and being rotatable in both clockwise and counterclockwise directions, a cylinder having a predetermined inner volume, and a roller rotatably installed on an outer circumferential surface of the eccentric portion so as to contact an inner circumferential surface of the cylinder. The roller performs a rolling motion along the inner circumferential surface of the cylinder and forms a fluid chamber therewith. A vane is elastically installed in the cylinder, contacting the roller, and upper and lower bearings are respectively installed at upper and lower portions of the cylinder to rotatably support the driving shaft and hermetically seal the inner volume of the cylinder. A compression mechanism forms different sizes of compressive spaces in the fluid chamber based on a rotational direction of the driving shaft.