A cutting tool for tube cutting machines includes a tool holder and a dismountable holder blade having replaceable cutting inserts. The tool holder includes a basic body, as well as a support body for the holder blade. There is arranged between the basic body and the support body a set-up body, by means of which the support body, and thereby the holder blade, can be set and fixed in the exact, desired spatial positions in the machine without time-consuming measuring and fine adjustment operations. In addition, the holder blade is fixed in the support body by means of a single simple screw, which allows a flexible mounting and dismounting of the same.