An image reading apparatus includes an image reading unit that can move along a scanning direction, and reads primary image data from a medium arranged on a medium arrangement surface by moving the image reading unit from a home position to a sub-scanning direction. The image reading apparatus further includes a determining unit that determines the presence or absence of the medium on the medium arrangement surface based on determination image data that is different from primary image data, and read by the image reading unit at a determination position arranged between the home position and a reading-end position of the primary image data.