PURPOSE: To prevent any distortion of tooth flanks finished, by adopting a tool that has for the right and left flanks a cutting edge geometry conforming to setting parameters that are effective during the removal of chippings by the respective cutting edges.

CONSTITUTION: An axial slide 2 movable in a Z-direction carries a radial slide 3 movable in an X-direction with relation to the axial slide 2. The radial slide 3 is provided with a gear cutting head 4 rotatable about an axis of rotation. The head 4 is adapted to move together with the radial slide 3. A stationary bed 1 is mounted thereon with a fixed workpiece spindle unit 6. The gear cutting head 4 and workpiece spindle unit 6 have spindles 7 and 8 that hold a tool 9 and a workpiece 10 respectively. During machining of the workpiece 10, the tool 9 and workpiece 10 are provided with basic rotation as well known.