PURPOSE: To reduce the whole size of a rotary compressor and to improve overall operating efficiency by utilizing the internal space of a motor section, and constituting a compression zone in the motor section without constituting them separately.

CONSTITUTION: When a cylinder 14 rotates counterclockwise and a vane 19 is angled at 45 degrees, refrigerant gas is made to flow into a suction chamber 23 made up of a tip sliding pin 21 and the vane 19 through a suction passage 16a of a stator shaft 16. When a cylinder 14 rotates and the angle comes to about 135° and 215°, volume in the suction chamber 23 is gradually increased, while volume in a compression space 24 is gradually decreased whereby the refrigerant gas is compressed. In this constitution, if pressure in this compression space 24 goes up more than a specified value, a one-way valve 17 is opened and the refrigerant gas is discharged out of an exhaust port 18 through a discharge pipe 22.