An image reading apparatus includes: a light emitting element array that includes plural light emitting elements arranged in line in a first scan direction of a document; a guiding unit that guides light entering from the light emitting element array, and that emits the light toward a reading position of the document while diffusing the light; a light receiving unit that receives reflected light from the reading position irradiated with the light from the light emitting element array through the guiding unit; and a scan unit that moves the reading position of the document in a second scan direction, the reading position being a position read by the light receiving unit.