EXPOSURE CONTROLLER

PURPOSE:To enable conversion which has good order and no error by necessary filters by providing a position detection sensor and an origin detection sensor and setting the necessary filters on an optical axis of exposure. CONSTITUTION:A window 12B is bored in each prism surface 12A of a hexagonal prism rotary body 12, and the filters 13A - 13F are provided; and each prism surface is hollow and a rod lamp 11 is contained in the center part. Position detection marks 14A - 14F are provided at the end parts of the respective prism surfaces 12A, an origin detection mark 15 is provided at the end part of one prism surface 12A, and the position detection sensor 14H and origin detection sensor 16 are fixed as the detection sensors for the respective marks to the frame of an exposure box 18 separately from the rotary body 12. Then a document D and a photosensitive material film F where it is printed are set one over another at the lower part of the exposure box 18, and moved for scan exposure with filter colors. Consequently, the position detection marks and origin detection mark are detected by the detection sensors respectively and the filters stop corresponding to the slit of a reverse surface as set.