An image reading apparatus including: a paper supply section; a transporting path for transporting a document supplied from the paper supply section; a first sensor which reads an image on a first surface of the document from one side of the transporting path; a second sensor which reads an image on a second surface of the document from the other side of the transporting path; and an image processing section which is constituted so as to correspond to a first reading mode in which two sides of the document are read using the first sensor plural times, and a second reading mode in which two sides of the document are read using the first sensor and the second sensor, and which makes a registration position and direction of an output image in both the first and second reading mode the same.