An image reading apparatus includes a first unit, a second unit, a motor, and a power transmission mechanism. The second unit is configured to be rotated in relation to the first unit and configured to be closed onto, and opened away from, the first unit by being rotated. The motor is provided in the first unit. The power transmission mechanism transmits motive power of the motor from the first unit to the second unit. The power transmission mechanism includes a first gear and a second gear. The first gear has the same axial center of rotation as that of the second unit. The second gear is provided in the second unit and is in mesh with the first gear.