An electronic control system is programmed to control movement of a cutting tool relative to a rotating workpiece. After engagement of the stock, the tool is controlled to follow a curved path until the cutting surface of the tool reaches a predetermined depth of cut in the stock. The tool is then controlled to follow a straight/linear path, with the cutting surface of the tool engaged with the stock at said predetermined depth of cut. The control system varies the feed rate as the tool rolls into cut along a known path of curvature, to control the thickness of the material which is removed as the tool rolls into cut, e.g. to induce fracture as the material begins to coil. The feed rate as the tool rolls into cut is programmed to vary in relation to an arc of engagement between a cutting surface of the cutting tool and the stock into which the cutting tool is being moved.

Command data indicating a command path of a tool is generated on the basis of tool data created on the basis of an inclination and a shape of the tool, and interpolation data for each interpolation period is generated and outputted. When a command block is a block commanding skiving processing, correction data for correcting the command path is generated on the basis of the tool data stored in the tool data storage unit, and the correction data corresponding to interpolation data outputted by an interpolation unit is outputted.