Abstract: The invention relates to a threading tool for internal threads with a cutter holder which is displaceably mounted on a cutter holder carrier shaft co-axial to the main axis of the rotatable tool which coincides with the thread axis during the cutting process, whereby the said cutter holder shaft is moved forwards and backwards periodically with the forward feed corresponding to the thread pitch in the direction of the main axis in the thread chasing operation by a cam control with a camshaft co-axial to the cutter holder shaft and rotating with a differential speed relative thereto, whereby through a corresponding radial displacement of the cutter holder the cutter is raised during return travel and in the thread chasing operation is set to engage lower and lower from one thread chasing operation to the next up to the final cutting depth.