Abstract: A screw compressor includes a compressor body and a shell and tube heat exchanger for cooling of a compressed air discharged from the compressor body. A tube provided in the shell and tube heat exchanger has both ends each having a cylindrical shape, and a center part formed as a multi-lobate tube to have a corrugated shape with crest portions and trough portions alternately arranged in a circumferential direction. The multi-lobate tube provided at the center part of the tube is formed to have a multi-lobate spiral shape through twisting. Size reduction of the shell and tube heat exchanger may make the screw compressor compact as a whole.