PURPOSE: To provide an oilless rotary compressor unit, especially an oil-free screw compressor unit, applicable in a place where no cooling water can be obtained.

CONSTITUTION: There are provided an oilless rotary compressor 1 comprising a male rotor and a female rotor enclosed in a casing with a cooling jacket in such a way as to be rotated being meshed with each other, at least one cooler for cooling high temperature discharge gas from the compressor 1, a radiator 13 for cooling refrigerant liquid run through the cooling jacket, and a cooling fan with a duct for air-cooling the cooler and the radiator 13. The cooling jacket and the radiator 13 are connected to form the closed circuit of refrigerant liquid. The refrigerant liquid air-cooled at the radiator is run through the cooling jacket to liquid-cool the compressor 1, and the high temperature discharge gas from the compressor 1 is air-cooled by the cooler. A circulating pump provided at the closed circuit of the refrigerant liquid is disposed on the refrigerant liquid outflow side of the radiator 13.