In a multi-column electron beam exposure apparatus for performing exposure treatment in parallel by arranging a plurality of column cells on a wafer, a relationship between exposure intensity and a line width for each column cell is obtained (Steps S41 and S44). Then, correction parameters are obtained, which allow a relationship between exposure intensity and a line width for a correction target column cell to coincide with a relationship between exposure intensity and a line width for a reference column cell selected from among the plurality of column cells (Steps S43 and S46). Thereafter, exposure time of each column cell is obtained by correcting the exposure time of the reference column cell based on the correction parameters thus obtained.
