An apparatus for forming a latent image of an identification data in an edge portion of a new photosensitive film is disclosed here. The apparatus comprises editing unit to edit the identification data and an exposure position data, a memory to store the edited data, a register for registering an identification data from the memory and exposing unit to form a latent image of the registered identification data on the photosensitive film based on the exposure position data and synchronized with the feeding of the photosensitive film.