The invention relates to a collet chuck (1) for clamping a preferably cylindrical tool shank with a chuck body (2) of a collet (3) and an union nut (4), which are matched in such a way that the collet (3) can be driven into the chuck body (2) by tightening the union nut (4) such that it secures the tool shank in the collet chuck (1) ready for operation, wherein the collet (3) and the union nut (4) are permanently connected to one another and at the same time connected in a rotatable manner relative to one another.