To a cell library pattern which makes the basic constitution of a semiconductor circuit pattern, OPC processing is performed beforehand, and a semiconductor chip is produced using this cell library pattern. Since it is influenced by the pattern of the cell arranged to the circumference and the pattern arranged around other cells at this time, correction processing (optimization processing) is performed. The part of this correction processing is a portion in which a pattern faces between cell boundaries in the inside of the region specified from the cell boundary, and proximity effect correction is performed by making the width, the length, and the position of this portion into variables. Or proximity effect correction is performed by making a polygon into a variable. Or sizing is done and proximity effect correction is performed.