An image reading apparatus includes a shooter where a first mounting surface that is inclined with respect to a horizontal plane is formed thereon, a stacker, a supporting unit that movably supports the stacker in such a manner that the stacker is arranged in a first region or a second region, a conveyance unit that conveys a document from the shooter to the stacker when the stacker is arranged in the first region, and a reading unit that reads an image from the document when the document is conveyed by the conveyance unit, wherein a surface area of a region of the first mounting surface that is covered by the stacker when the stacker is arranged in the first region is greater as compared with that when the stacker is arranged in the second region, and the stacker is formed to be capable of being lengthened or shortened.