Provided is a technique capable of improving the dimensional accuracy of a transfer pattern in a lithography technique in which EUV light is used and the EUV light is incident obliquely on a mask and an image of the EUV light reflected from the mask is formed on a semiconductor substrate (resist film), thereby transferring the pattern formed on the mask onto the semiconductor substrate. The present invention is based on a lithography technique in which EUV light is used and an exposure optical system in which the EUV light is obliquely incident on a mask is used. In this lithography technique, an absorber and a difference in level are formed on the mask, and a projective component projected on a mask surface out of a direction cosine component of the incident light is set to be almost orthogonal to an extending direction of the difference in level.