There are provided a rear wheel (7) rotatably provided in a body (2), a seat (32) disposed on a top surface side of the body (2), a seat link mechanism (33) by which the seat (32) is supported to be movable up and down between a raised position and a lowered position on the top surface side of the body (2), and a brake mechanism (41) which inhibits the rear wheel (7) from rotating in interlock with the seat link mechanism (33), when the seat (32) is raised from the lowered position to the raised position.
