A tool path is generated with procedures that include: one of the processing points (Pi) on a multiple rows of tool paths (PA) obtained by connecting multiple prescribed processing points sequentially with straight lines is set as a revision processing point (Pt), points on the multiple rows of tool paths are set as distance calculation points (Pu), and the distance (L) from the revision processing point (Pt) to each of the distance calculation points (Pu) is calculated; the distance calculation points (Pu′) for which the distance (L) is within a prescribed value (ΔL) are extracted; the mean values of the position data for the distance calculation points (Pu′) and the position data for the revision processing point (Pt) are calculated; and the position data is revised by means of the mean values, and a new tool path (PA′) is created.