Abstract: A throttle device for a twin-shaft screw machine having a housing with two mutually penetrating bores in which respective screw shafts are arranged. Each bore has an outer gap sleeve and each shaft has an inner gap sleeve, the sleeves being mutually axially displaceable in order to generate or modify a throttle gap therebetween. The throttle gaps are formed, in each case, between cylindrical outer circumference on the respective inner gap sleeve and a cylindrical internal bore on the respective outer gap sleeve to provide an annular cylindrical gap of constant width but variable length. Each outer gap sleeve is connected to at least one sliding bolt which passes through an associated slot in the housing and through which the outer gap sleeve can be moved axially from outside the housing.