Abstract: A device for holding tools for machine tools, includes at least one interchangeable holder and one base holder. Each interchangeable holder includes two interchangeable-holder guiding elements which are engaged with base-holder guiding elements of the base holder. Furthermore, each interchangeable holder comprises an interchangeable-holder coolant channel comprising an interchangeable-holder coolant-channel opening in one of the interchangeable-holder guiding elements, which comes into contact with a base-holder coolant-channel opening of a base-holder coolant channel, which is arranged on a base-holder guiding element. First guiding elements—either the interchangeable-holder guiding elements or the base-holder guiding elements—have a convex semicircular cross-section. The cross-section has a flat area containing the vertex of the semicircle, or it has two widened areas which are arranged in mirror symmetry on the semicircle.