A local exposure method includes steps of: dividing a large block into a plurality of small blocks; setting irradiation illuminances different in a stepwise fashion; controlling light emission of light emitting elements based on the irradiation illuminances respectively set for the small blocks for a photosensitive film on a substrate moving with respect to light emitting elements; developing the photosensitive film having been subjected to exposure processing by irradiation by the light emitting elements; measuring a residual film thickness of the photosensitive film for each of the small blocks to obtain correlation data between the illuminance set for the small block and the residual film thickness; and obtaining a required illuminance of irradiation to each of the large blocks from a target residual film thickness of the photosensitive film set for each of the large blocks based on the correlation data.