A transport system according to the present disclosure includes a mobile robot that moves with a wagon mounted thereon, the wagon having a plurality of convex portions that protrude downward. The mobile robot includes a platform that has a mounting surface on which the wagon is placed and that enters under the wagon, a raising and lowering mechanism that raises and lowers the platform to deliver the wagon, a plurality of concave portions provided corresponding to the plurality of convex portions of the wagon, an optical sensor provided on a side surface of at least one concave portion among the plurality of concave portions, and a detection unit that detects that at least one of the plurality of convex portions is inserted into the at least one concave portion according to a detection result of the optical sensor.