An image reading apparatus includes a medium mounting portion configured to mount a medium; a feeding means configured to feed a medium from the medium mounting portion; at least one edge guide each configured to regulate a corresponding one of at least one medium width direction edge of the medium having been mounted on the medium mounting portion; a reading means configured to read the medium and disposed on a further downstream side than the at least one edge guide in the medium feeding direction; and at least one medium detection means configured to detect the medium and disposed on a further downstream side than the at least one edge guide in the medium feeding direction and further outside in the medium width direction than at least one edge regulation position for the edge regulation by the at least one edge guide.