A clamping device for machine tools, comprising a chuck (1.1) and a drawbar (1.2) for clamping separate pallets (1.3), with a bayonet-connection via rotational motion of that drawbar (1.2). Rotational motion of the drawbar (1.2) is guided and determined by means (2.5, 2.7, 2.6, 2.4, 2.12, 3) provided in the chuck housing (2.3) interacting with the drawbar (1.2, 2.13). The drawbar (1.2) is turnable mounted in the chuck (1.1) to impede the drawbars extraction out of the chuck, independent if the drawbar (1.2) is in clamping or unclamped condition.