The object of the invention is to extend the life of the light source while uniformizing the illuminance intensity in the main scanning direction. The invention is based on a light source of image reading apparatus comprised of film layers laminated on a transparent substrate in the order of a transparent electrode, an area light emitter and a metal electrode, and emitting light by impressing a specific voltage on these two electrodes. And an area light emitter column configured by arranging area light emitters corresponding to each color of R (red), G (green) and B (blue) in the sub scanning direction, or a monochrome area light emitter is arranged repeatedly in the main scanning direction. Accordingly, even when somewhere in the light emitting element has a defect like the film thickness is thin, the current gathering at this point with the low resistance value becomes a very small volume. Therefore, it would not occur that the film burns out from here.