Abstract: A geometric data correction method is applicable to geometric data-element data comprising a plurality of line segments and circular arcs. When geometric data elements that should originally be interconnected cross or become separated from each other, the offset between geometric data elements is corrected automatically. This saves a great amount of time in comparison with that needed for redrawing of the geometric data elements. The method includes a topology recognition step of recognizing the topology of the geometric data elements, a geometric-parameter alteration step of correcting the offset of geometric data elements by altering geometric parameters, which define each geometric data element, with regard to all geometric data elements while maintaining the topology thereof, and an end-point decision step of deciding end points accompanied by enlargement/reduction of the geometric data elements.