In the present invention, the line widths within a substrate of an etching pattern are measured for a substrate for which photolithography processing and an etching treatment thereafter have been finished. The line width measurement results are converted into the line widths of a resist pattern using relational expressions which have been obtained in advance. From the converted line widths of the resist pattern, coefficients of a polynomial function indicating variations within the substrate are calculated. Next, a function between line width correction amounts for the resist pattern and temperature correction values is used to calculate temperature correction values for the regions of the thermal plate to bring the coefficients of the polynomial function close to zero. Based on each of the calculated temperature correction values, the temperature for each of the regions is set.