To solve the problems that an entire wheelchair is inclined to the left or right by the difference between the ground height of its left wheel and that of its right wheel, thereby the wheelchair could turn over and a riding comfortability is reduced when both wheels are put on a place with a height difference between the left and right wheels in a conventional wheelchair.

The wheels 2 respectively on left and right sides are respectively attached to left and right wheel frames 21 and the respective wheel frames 21 are connected by a parallel linking mechanism 4 provided with plural linking pars 41 and 42 up and down. The length direction center parts of the respective upper and lower linking bars 41 and 42 of the parallel linking mechanism 4 are respectively pivoted to a supporting frame 11 suspended from a seat frame 1 and the seat frame 1 is provide with a guide device 5 for inhibiting the vertical axis P-P of the sitting frame 1 from being tilted to the left and right for the respective wheel frames 21. Also, even when the respective left and right wheels 2 get on a step surface with the height difference between the left wheel and the right wheel, the parallel linking mechanism 4 is deformed and the seat surface part 12 of the seat frame 1 is maintained in a horizontal posture at all times.