The invention relates to a document image capturing device. In the document image capturing device having a module capable of moving, it is desired to further improve the dust proof performance while the load generated when the module is moved is maintained at a certain level. The document image capturing device includes an image capturing module for capturing an image of a document, and a first aperture portion, an illumination module movable between the image capturing module and a document conveying path and including a light source for illuminating the document and a second aperture portion, and a dustproof unit for sealing between the first aperture portion and the second aperture portion regardless of movement of the illumination module. The dustproof unit includes a first film attached to cover an entire periphery of the first aperture portion and a second film attached to cover an entire periphery of the second aperture portion, and the first aperture portion and the second aperture portion are arranged so that a reflection light from the document illuminated by the light source passes through the first aperture portion and the second aperture portion.