SCREW COMPRESSOR

PROBLEM TO BE SOLVED: To provide a screw compressor capable of reducing the discharge pressure loss and improving the performance by reducing the flow passage resistance of a discharge port section.SOLUTION: The screw compressor includes: a casing 1; a screw rotor 2 which is rotatably accommodated in a casing and has a plurality of screw grooves 22; and a pair of gate rotors 4 respectively having a plurality of teeth 41 to be engaged with a screw groove of the screw rotor. Here, a space formed by the casing, the screw groove of the screw rotor and the teeth 41 of the gate rotor is used as a compression chamber 5 of working gas, the screw compressor further includes a capacity control unit 10 for adjusting the suction amount of the working gas into the compression chamber by communicating the compression chamber 5 with a low-pressure chamber 8 in the casing, and the compressed working gas is exhausted from an exhaust port 7. The capacity control unit 10 is separated from the exhaust port 7, and arranged at the position separate from the exhaust port in the circumferential direction.