To provide a mask for reduction projection exposure which facilitates the manufacture of an auxiliary pattern and practicizes an auxiliary pattern method.

A half-tone phase shift film 103 is formed entirely over one surface of a transparent substrate 101 and a light shield film 102 is formed on the half-tone phase shift film 103 corresponding to the main pattern of the center part of the substrate. Further, a main pattern is formed by boring a light shield film 102 and the half-tone phase shift film 103 at the center part of the substrate and the half-tone phase shift film 103 at the periphery of the main pattern 1 is bored to form the auxiliary pattern 2.