Disclosed is a method for manufacturing a semiconductor device. The method includes: a first pattern forming step of forming, on a pattern forming target film, a first film that is patterned to have a first pattern that includes lines which are aligned with each other with spaces of a predetermined interval being interposed therebetween, and include a portion separated by using a first cut mask; a step of forming a second film to cover a surface of the first film; and a second pattern forming step of forming a pattern forming target film that is patterned to have a second pattern, by separating a portion of the space of the first step using a second cut mask. The first and second cut mask includes a plurality of openings or light shielding portions that have equal shapes, respectively.