PURPOSE: To make corrections with high accuracy without damaging a glass substrate by correcting a black defect by a laser correcting device which has low correction accuracy and forming a white defect on a light shield pattern, and then correcting the white defect by a converged ion beam correcting device which has high correction accuracy.

CONSTITUTION: When the black defect 2 (excessive part of light shield film) of the mask for exposure where the light shield pattern 1 is formed of a light shield film on a transparent substrate is removed, the black defect part is irradiated with a converged laser beam to remove the light shield film of the black defect part, and at the same time the light shield film is removed even from a normal light shield pattern adjoining to the black defect part to form the white defect 5 (absence part of light shield film). Then organic gas is blown to the white defect part, which is irradiated with a converged ion beam to polymerize the organic gas, thereby depositing a carbon film on the white defect part. Consequently, the etching process of the glass substrate is omitted and the black defect can be corrected with high accuracy without damaging the glass substrate.