PURPOSE: To enable design data to be converted into exposure data automatically and easily without performing re-processing of the data, etc., even if a designer has failed to discriminate between the positive and negative types of a resist.

CONSTITUTION: It is determined whether a design data pattern is of a positive or negative type according to a pattern configuration database, and the determined positive or negative type of the design data pattern is compared with the positive or negative type of a resist included in a processing condition database and, when the design data pattern compared is different from the positive or negative type in the processing condition database, the different pattern is eliminated according to the pattern configuration database and then a correct pattern is newly originated according to the pattern configuration database, so that design data is corrected.