An image reading apparatus includes a document supporter, a guide, a carriage, and a reader. The carriage has a recessed portion. A first protrusion, a second protrusion, a third protrusion, a fourth protrusion, a fifth protrusion, and a sixth protrusion are provided on the recessed portion. Each of the first protrusion, the second protrusion, the third protrusion, and the fourth protrusion has a distal end portion in a protruding direction thereof, and the distal end portion is in contact with the guide when the carriage is mounted on the guide. A protruding amount of each of the fifth protrusion and the sixth protrusion in a protruding direction thereof is less than that of each of the first protrusion, the second protrusion, the third protrusion, and the fourth protrusion.