A mask having mask patterns for the transfer of a desired circuit pattern, a method for manufacturing the mask, and a semiconductor device manufacturing method using the mask, are provided. There are extracted two rectangular aperture patterns which are adjacent each other in an obliquely disposed state with respect to an X axis in an XY plane. The thus-extracted two rectangular aperture patterns are rotated at a certain angle so that a pattern edge corresponding to one side of one of the rectangular aperture patterns and a pattern edge corresponding to one side of the other rectangular aperture pattern are opposed in parallel to each other. The two rectangular aperture patterns thus rotated at a certain angle are then subjected to optical proximity effect correction to form two corrected rectangular aperture patterns.