A multi-stage screw compressor includes a plurality of stages of compressor bodies that compress a gas in sequence. Each of the stages of compressor bodies has both male and female rotors that are housed revolvably in a casing in a mutually meshing state. The male and female rotors each include a rotor lobe section having a suction-side end face and a discharge-side end face on one end and the other end thereof in the axial direction and having a twisted lobe extending from the suction-side end face to the discharge-side end face. The male and female rotors in a downstream-stage compressor body of at least one certain stage, excluding an upstream-stage compressor body as the first stage, among the plurality of stages of compressor bodies are each configured such that their lead increases from the suction side in the axial direction of the rotor lobe section toward the discharge side.