In devices for generating a path of a tool of a processing machine by way of computer simulation, an NC program is created using a generated processing path. The NC program used to be corrected by verification of actually moving the processing machine. In contrast, the disclosed processing path generation device has been constituted to be provided with a means for calculating a closest distance and direction from a relationship of a position and posture between a tool and a work at an arbitrary point upon the processing path; a means for imparting a color determined by the closest distance and the direction calculated at the point upon the processing path; a means for panoramically displaying the color imparted to the work; and a means for correcting the relationship of the a position and posture between the tool and the work on the basis of information from a display device.