An image reading apparatus includes a document positioning plate configured to have a document positioned thereon, a conveyance belt configured to convey the document to the document positioning plate, an image reading unit configured to read an image of the document positioned on the document positioning plate, and an image unevenness reducing unit configured to reduce image unevenness caused by the conveyance belt deflecting in a main scanning direction. The image unevenness reducing unit corrects the readout image based on correction coefficients each corresponding to a combination of a sub scanning position and a main scanning position of the image.