A mask manufacturing method suitable for an exposure method wherein a mask on which a desired pattern and a supplementary pattern with formations smaller than those of the desired pattern are arrayed is illuminated, and the light which passed through the mask onto a member to be exposed is projected via a projection optical system, said method comprising a selecting step for selecting one of the following three supplementary patterns, a first supplementary pattern wherein said supplementary pattern is disposed at a position where a line extending in the vertical direction as to the pitch direction from a certain desired pattern hole of said desired pattern, and a line connecting the supplementary pattern hole closest to said certain desired pattern hole in the vertical direction with said certain desired pattern hole, intersect at an angle of 0.degree., a second supplementary pattern wherein said angle is 0.degree. or more but less than 45.degree., and a third supplementary pattern wherein said supplementary pattern supplementary pattern is disposed at a position where said is disposed at a position where said angle is 45.degree..