Tool path part program modification system of NC machine tool

A tool path part program modification system of an NC machine tool according to an aspect of the present disclosure, includes: a human-machine interface unit which receives a tool path part program having one or more processing blocks; an NC kernel unit which interprets the part program inputted to the human-machine interface unit for each processing block, and generates each processing block information; a tool path modification module unit which sequentially calls the processing block information interpreted by the NC kernel unit, and modifies a consecutive rapid transfer processing block group such that tool paths are reduced, when the consecutive rapid transfer processing block group is present in which the predetermined reference number or more of processing blocks including rapid transfer commands are consecutively included; and a simulator unit which simulates the part program for each processing block interpreted by the NC kernel unit.