According to one embodiment, on a substrate, a resist layer is laminated on an upper side of a pattern formation layer on which a desired pattern is formed. A diffraction pattern that diffracts exposure light irradiated on the substrate is formed further on the upper side than the resist layer. Overall exposure is performed from above the diffraction pattern using a deformed light having illumination light source shape determined according to the desired pattern. Diffracted light diffracted on the diffraction pattern by the exposure is irradiated on the resist layer.