A oil-cooled type screw compressor of the present invention includes a compressor main unit storing a pair of male and female screw rotors driven by a motor and meshing with each other, a cooling fan provided independently to the motor for blowing air toward the motor, and control means for receiving a detected temperature signal from a temperature detector for detecting the coil temperature of the motor, and conducting control for increasing/decreasing the fan rotation speed of the cooling fan according to the coil temperature so as to maintain the coil temperature within a permissible range. It is possible to use the coil current of the motor or the motor rotation speed and the discharge pressure in place of the detected temperature signal. This constitution provides a screw compressor which offers fan-removed heat quantity not excessive or insufficient with respect to the motor heat generation quantity, and realizes sufficient cooling for the motor, and energy saving.