The present invention provides a screw compressor wherein, even if a gate rotor flexes owing to a temperature differential between a casing and a screw rotor during operation of a compressor, the gate rotor is prevented, with a simple configuration, from biting into the screw rotor, which reduces the amount of wear of the gate rotor and prevents a decline in the compressor's performance. The gate rotor (3) comprises a gate rotor main body (30) and a shaft (40) to which the gate rotor main body (30) is attached. An elastic body (5) is disposed between (S) the axle (41) of the shaft (40) and the hole (32) of the gate rotor main body (30).