Numerical control device having tool correction function in skiving processing

A numerical control device controlling a machine tool which performs skiving processing of cutting processing on a rotational symmetry surface of a rotating workpiece with a tool, on the basis of a processing program including a command block, the device comprising:

• a tool data storage unit that stores tool data created on the basis of at least one of an inclination of the tool and a shape of the tool;
• a processing program analysis unit that reads out and analyzes a command block from the processing program, and generates and outputs command data indicating a command path of the tool which is commanded by the command block;
• an interpolation unit that performs interpolation processing on the basis of the command data, and generates and outputs interpolation data for each interpolation period of the interpolation processing;
• and
• a correction unit that determines, when the command block is a block commanding the skiving processing, whether a current position of the tool is between a cutting start point and a cutting end point, and that generates, when the current position of the tool is between the cutting start point and the cutting end point and when the command block is the block commanding the skiving processing, correction data for correcting the command path for each interpolation period of the interpolation processing on the basis of the tool data stored in the tool data storage unit and the current position of the tool being between the cutting start point and the cutting end point, and outputs the correction data corresponding to the interpolation data outputted by the interpolation unit.