There is disclosed a method of producing a design layout by optimizing at least one of design rule, process proximity correction parameter and process parameter, including calculating a processed pattern shape based on a design layout and a process parameter, extracting a dangerous spot having an evaluation value with respect to the processed pattern shape, which does not satisfy a predetermined tolerance, generating a repair guideline of the design layout based on a pattern included in the dangerous spot, and repairing that portion of the design layout which corresponds to the dangerous spot based on the repair guideline.