An image reading apparatus includes a conveying unit to convey a document, first and second reading units, a reception unit, a selection unit, and a setting unit. The first reading unit generates image data form a document first side and the second reading unit generates image data from a second side in parallel with the first reading unit reading. The reception unit receives settings regarding a size, an orientation, and a document opening direction of the document. The selection unit selects either a first reading method causing the first and second reading units to read per the set size, and a second reading method causing the first reading unit to read the first side per the set size and causing the second reading unit to read an entire second side. The setting unit sets image data corresponding to the document second side reading by the second reading method.