A rotary compressor is provided with a cylinder which defines a cylinder chamber and a piston disposed in the cylinder chamber. The piston includes a roller which performs a revolving motion within the cylinder chamber and a vane which partitions the interior of the cylinder chamber into a suction chamber and a compression chamber. A small space is provided so as to communicate with the compression chamber in only a predetermined section without communicating with the suction chamber so as to suppress noise generated by a pressure fluctuation in the interior of a compression chamber and, at the same time, can prevent the occurrence of a loss induced by re-expansion of a refrigerant remaining in a small space and a loss induced by return of the refrigerant to a suction chamber.