To enable a passenger to ride a "roller coaster" in a standing position, the inventive device includes a seat placed between the legs of the passenger, a back member with a headrest incorporated in it, and two harnesses which provide retention of the passenger from above as well as lateral retention of his head and good front and lateral retention of his body. One of the harnesses is movable and can be swung upwardly to enable easy access to the subject device by the passenger and to enable a ve...