PURPOSE: To handle a truck without being influenced by handling conditions and to eliminate scaffold working to promote work efficiency by using a free- running type high place working truck having a driving wheel device and an adjusting wheel device to truck body for working, etc., in a common channel.

CONSTITUTION: First of all, a truck body is constituted of a pipe frame such as vertical members 1, cross member 2 and reinforcing members 3, and it can be folded freely with a diagonal line as the center, so that the truck can be handled even in a narrow handling section by folding it in the case of handling. An enclosed body 4 with handrails and a working bench 5 spreading a plurality of floor boards thereon are mounted to the upper side of the truck body. After that, a driving wheel device 6 and an adjusting wheel device 7 are provided to the truck body, and work efficiency is increased as a free-running truck. Then, a pair of overturning prevention arms 14 and an overturning prevention device having a guide roller are provided to the truck body to prevent the truck from overturning. In the case of working at the working bench, the movement of an adjusting wheel 11 can be prevented by an adjusting stopper 12.