A rotary compressor comprising: - a driving shaft being rotatable clockwise and counterclockwise, and having an eccentric portion of a predetermined size; - a cylinder forming a predetermined inner volume; - a roller installed rotatably on an outer circumference of the eccentric portion so as to contact an inner circumference of the cylinder, performing a rolling motion along the inner circumference and forming a fluid chamber to suck and compress fluid along with the inner circumference; - a vane installed elastically in the cylinder to contact the roller continuously; - upper and lower bearings (24, 25) installed respectively in upper and lower portions of the cylinder, for supporting the driving shaft rotatably and sealing the inner volume hermetically; and - an oil path configured to allow oil to uniformly flow between the bearings (24, 25) and the driving shaft; characterized in that the rotary compressor further comprises: - discharge ports (26a, 26b) provided at the upper bearing and communicating with the fluid chamber; - suction ports (27a, 27b, 27c) provided at the lower bearing and communicating with the fluid chamber and being spaced apart from each other by a predetermined angle; and - a valve assembly provided between the cylinder and the lower bearing for selectively opening any one of the suction ports (27a, 27b, 27c) according to the rotation direction of the driving shaft, wherein compression spaces that have different volumes from each other are formed in the fluid chamber according to the rotation direction of the driving shaft such that two different compression capacities are formed. - a driving shaft being rotatable clockwise and counterclockwise, and having an eccentric portion of a predetermined size; - a cylinder forming a predetermined inner volume; - a roller installed rotatably on an outer circumference of the eccentric portion so as to contact an inner circumference of the cylinder, performing a rolling motion along the inner circumference and forming a fluid chamber to suck and compress fluid along with the inner circumference; - a vane installed elastically in the cylinder to contact the roller continuously; - upper and lower bearings (24, 25) installed respectively in upper and lower portions of the cylinder, for supporting the driving shaft rotatably and sealing the inner volume hermetically; and - an oil path configured to allow oil to uniformly flow between the bearings (24, 25) and the driving shaft; characterized in that the rotary compressor further comprises: - discharge ports (26a, 26b) provided at the upper bearing and communicating with the fluid chamber; - suction ports (27a, 27b, 27c) provided at the lower bearing and communicating with the fluid chamber and being spaced apart from each other by a predetermined angle; and - a valve assembly provided between the cylinder and the lower bearing for selectively opening any one of the suction ports (27a, 27b, 27c) according to the rotation direction of the driving shaft, wherein compression spaces that have different volumes from each other are formed in the fluid chamber according to the rotation direction of the driving shaft such that two different compression capacities are formed.