PURPOSE: To perform the smooth machining of the tip of an anchor pin in a short time by rotating bites with the edges located on a conical surface to be cut and synchronously rotating among the bites chip discharging rods which are then moved to an axis of rotation.

CONSTITUTION: When a spindle 1 is rotated by a motor 30, bites 3a-3c machine a metal rod 40 from its tip into a conical from as a slide table 35 moves forward, the tip of a chip discharging rod 22 in a chip discharging unit 20 passes among the bites 3a-3c to push chips toward a metal rod 40 and discharge the same to the outside with the cutting unit 20 moving forward. The bites 3a-3c during cutting are increased in number to serve for cutting as the spindle 1 moves forward, to perform smooth cutting for a short time. As the slide table 35 moves backward, the spindle 1 is set apart from the metal rod 40, the chip discharging unit 20 moves backward more quickly than the spindle 1 and stops once and the spindle 1 still moves backward, so that the tip of the chip discharging rod 22 is relatively protruded into an area among the bites 3a-3c of the spindle 1 to push the chips out again and remove the same.