A rotary compressor includes a driving shaft rotatable clockwise and counterclockwise, and 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 to contact an inner circumference of the cylinder; a vane installed elastically in the cylinder to contact the roller continuously; a first bearing installed in the cylinder, for supporting the driving shaft rotatably; a second bearing rotatably supporting the driving shaft and preliminarily storing the fluid to be sucked; discharge ports communicating with the fluid chamber; and a valve assembly having openings separated by predetermined angle from each other, 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 so that two different compression capacities are formed.