There is disclosed a graphic processing method in which a first figure skeleton apart from an outline of a figure by each equal distance in a central direction of the figure is calculated using at least one of a medial axis and a chordal axis with respect to a figure representing the outline of the object shape reflected in a digital image by a set of points, branch lines to the skeleton from a vertex of the figure in the calculated first figure skeleton are removed to obtain a second figure skeleton, and a curve coordinate system is defined using the second figure skeleton as one coordinate axis and using a distance between the second figure skeleton and the outline of the figure as the other coordinate axis with respect to data obtained by one circulation of the outline of the figure using one end point of the second figure skeleton as a start point and using the other end point as a terminal point to transform the coordinate of points on the outline of the figure into the other coordinate axis of the curve coordinate system.