To prevent a wheelchair from backward movement in an uphill slope.

A car frame is provided with a shift lever 22, a link mechanism 23 and a turning roller 34. The link mechanism 23 is interlocked with the turning operation of the shift lever 22. The turning roller 34 is a reversing prevention means to allow the rotating direction of wheels of the wheelchair only to one direction in accordance with the turning operation of the link mechanism 23. The turning roller 34 is provided with a one way clutch to allow only one way rotation and prevents the rotation in a reverse direction, a wheel hub 48 which engages and incorporates such journalling members as needle bearings and the like, and a rubber outer ring 49 covering around the outer circumference of the wheel hub 48.