In an image forming apparatus provided with an exposing section and a conveyor for conveying a plurality of light sensitive materials relative to the exposing section, the plurality of light sensitive materials are arranged in parallel in the conveying direction so that the exposing section is divided into plural exposing blocks corresponding to the plurality of light sensitive materials. There are provided a memory to memorize plural correction amounts each set based on a characteristic of one of the plurality of light sensitive materials, wherein the plural correction amounts are correlated with the plural exposing blocks in accordance with the corresponding light sensitive material; and a correcting section to correct the amount of light for each exposing block on the basis of the corresponding correction amount.