To prevent the overturn of a wheel chair when the wheel chair moves upward or downward on a staircase and when it gets on or off a bus, an electric car or the like.

A chassis 2 equipped with caterpillars on which suckers and developing plates are mounted is linked to both sides of a wheel base and outriggers 7a and 7b with casters are mounted freely developing positions after and before the chassis. A chair 4 is linked to the wheel base free to raise or level longitudinally through a wheel base center support shaft 1-4. In a handle 5 and a handle wheel 5-3, shafts 5-0 and 5-2 are vertically extended or reduced centered on the wheel base and the link lateral shaft 1-5 and the handle is raised or leveled longitudinally with the link lateral shaft as axis. Outriggers with casters and caterpillars having suckers and developing plates are mounted.