Provided is a treadmill. The treadmill includes a first frame and a second frame that are disposed in parallel with each other and a plurality of slats that extend perpendicularly to a disposition direction of the first frame and the second frame, are disposed between the first frame and the second frame, and are installed to move with respect to the first frame and the second frame, in which at least some of the plurality of slats include a support plate, which includes a base portion providing a first plane and a strength reinforcing portion that has a shape protruding from the base portion and has a cavity formed therein.