Abstract: The aberration measurement method can determine an aberration from a width of an image of a pattern line on a resist or from a ratio of light quantities upon measuring an amount of the aberration of the image formed by an optical projection system. This method further can measure an amount of a deviation of a position of the image of the pattern on the resist so that it can solve laborious work otherwise required by conventional technology that uses a complicated microscope such as a scanning-type electronic microscope. Moreover, the aberration can be determined by measuring a pitch width of a whole line-and-space pattern containing wedge-shaped lines or lengths of the wedge-shaped lines. This does not require to learn the absolute position of the image because a difference between the amounts of deviation of the positions of the different pattern images so that no such complicated microscope is not required.