Abstract: An automatic chamfering machine for chamfering the edge of teeth of internal gears or edge of slots of ring-like clutches is disclosed. Once the machine is set on the work (i.e., an internal gear or a ring-like clutch), it can be intermittently moved along the work at an interval corresponding to one tooth or slot to effect chamfering.The automatic chamfering machine according to the invention has at least one drive roller, which is held attracted to the work through excitation of a solenoid so that the machine will not fall from the work. The chamfering machine is moved along the work to an extent corresponding to one tooth, for instance, with the rotation of the drive roller attracted to the work to be automatically stopped at the next chamfering position. Then, a cutter is moved along the tooth surface while being rotated to effect chamfering.