Gas compressor

A gas compressor, comprising:

• a hollow cylinder member;
• a rotor rotatably disposed inside the cylinder member;
• a plurality of vanes attached to the rotor in a projectable and houseable manner, the plurality of vanes including leading ends which have contact with an inner circumferential surface of the cylinder member, so as to form a plurality of compression rooms inside the cylinder member, wherein
• a cylinder room which changes a volume of the compression room, and performs a gas compression cycle is formed between the cylinder member and the rotor,
• a suction section which sucks the gas is provided upstream of the cylinder room,
• a discharge section which discharges the gas is provided downstream of the cylinder room,
• a proximal section in which the cylinder member and the rotor come close to each other is provided in one position between the cylinder member and the rotor, so that a single cylinder room which performs the gas compression cycle one-time per one cycle for each compression room is formed, and
• at least one sub-discharge section, which maintains discharge pressure of the gas by releasing pressure of the compression room when the pressure of the gas in the compression room reaches the discharge pressure, is provided upstream of the discharge section.