A tool clamping device for a tool having a shaft which is accurate to size and which can be inserted into the receiving bore of a tool support, is provided with a clamping device which can be screwed on a screw thread of the tool support while the tool has a ring, which is arranged radially protruding in a clamping area. The ring extends in the circumferential direction and, with the shaft of the tool inserted into the receiving bore, the clamping device is axially supported against the ring (FIG. 2).