There is provided an image reading apparatus that, when double feeding of documents is detected by a double feeding detector, transports the documents in the reverse direction of the transport direction at least until the leading edges of the double-fed documents are positioned at the upstream side of transport roller pairs by rotating a separation roller and a retard roller so as to transport the documents in the reverse direction, and that thereafter transports the documents in the transport direction by rotating the separation roller so as to transport the documents in the transport direction. When the documents are transported in the reverse direction, the image reading apparatus sets a second rotation speed of the retard roller to be faster than a first rotation speed of the separation roller.