A semiconductor manufacturing method comprising, a data generating process including, acquiring a simulation light pattern that simulates a shape of a light exposure pattern formed on a substrate on the basis of design data of a semiconductor device, acquiring a simulation electron beam exposure pattern that simulates a shape of an electron beam exposure pattern formed by an electron beam exposure on the substrate on the basis of the design data, extracting difference information representing a shape difference portion between the simulation light pattern and the simulation electron beam exposure pattern, acquiring changed design data for modifying shape by changing the design data in accordance with the difference information, conducting the electron beam exposure on the substrate by use of the changed design data for modifying the shape.