An apparatus for removing burrs on billets has a supporting element and at least two arms extending from the supporting element. Deburring devices are driven in rotation by burrs of billets. The deburring devices are supported by the arms. The apparatus is driven rotatably and reversibly by a drive between a stand-by position wherein the apparatus is spaced apart from the billet to be deburred and a working position wherein the deburring devices are close to the billet to be deburred and are able to contact a burr.

The present invention is to eliminate formation of a shape that induces reduction of fatigue strength, without forming a step part, in a shape portion formed by machining. This processing apparatus includes end mills having bottom blades formed in a curved convex shape, and arcuately formed radial blades provided in corner areas; a drive section for driving the end mills; and a control unit for controlling the drive unit. The control unit includes a planar-shape-formation unit that controls the drive unit so as to form, in a workpiece, only a planar-shape portion adjacent to a fillet shape portion in such a manner that a portion of the shape to be processed corresponding to the fillet shape portion is left unprocessed; and a fillet formation unit that controls the drive unit so as to form the fillet shape portion in the workpiece in a single pass using the radial blades.