A screw compressor comprising: a pair of male and female screw rotors; and an air-cooled heat exchanger, wherein the air-cooled heat exchanger is provided above a motor for driving the compressor body; wherein, with respect to a cooling wind for the air-cooled heat exchanger, the air-cooled heat exchanger is inclined to the upstream side; wherein the uppermost portion of a unit suction port for the air-cooled heat exchanger cooling winds is positioned below the uppermost portion of the air-cooled heat exchanger positioned at the uppermost portion; wherein the lowermost portion of the unit suction port for the air-cooled heat exchanger cooling wind is positioned below the lowermost portion of the air-cooled heat exchanger positioned at the lowermost portion; and wherein the cooling wind for the air-cooled heat exchanger is exhausted from a ceiling portion of the compressor unit. With this structure, it becomes possible to provide a compact screw compressor with less noise whose installation area can be reduced.