A rotary compressor includes a rotation mechanism, an annular piston and a blade. The rotation mechanism has a cylinder with an annular cylinder chamber. The annular piston is contained in the cylinder chamber eccentrically from the cylinder and sectioning the cylinder chamber into an outer compression chamber and an inner compression chamber. The blade is disposed in the cylinder chamber and sectioning each of the inner and outer compression chambers into a high-pressure side and a low-pressure side. The rotation mechanism compresses a fluid by relatively rotating the cylinder and the piston. The outer compression chamber serves as a low-stage side compression chamber for compressing a low-pressure fluid into an intermediate-pressure fluid. The inner compression chamber serves as a high-stage side compression chamber for compressing the intermediate-pressure fluid compressed in the low-stage side compression chamber into a high-pressure fluid.