A sharp corner judgment means judges as to whether a corner of cut shape in
a workpiece is a sharp corner is not on the basis of a machining program.
When the corner is regarded as the sharp corner, an additional locus
producing means for producing sharp corner produces an additional locus
for producing sharp corner when machining on the corner regarded as the
sharp corner, and a sharp corner machining execution means executes
machining on the corner on the basis of the produced additional locus for
producing sharp corner. Then, the additional locus for producing sharp
corner can be automatically produced for the sharp corner so as to execute
machining.
