Described is a coupling system for cutting shank tools with which a stationary connection can be produced between coaxial parts of the shank tool in the direction of rotation and in the axial direction. The coupling system includes a holding fixture formed in a first part for a centering extension provided on a second part to be connected, a drive device, and a clamping device which can be actuated externally by an adjusting device and with which both parts can be pressed against each other through a prop ring surface pairing. The clamping device includes a connecting rod that is mounted symmetrically like a pendulum in the first part and that extends into a coaxial recess in the second part and forms a conical section there, through which the connecting rod can be placed under tension by the adjusting device braced on the second part. This generates pure axial tension which can be introduced, through a large, ring-shaped flat brace, without transverse force into the shank parts to be coupled.