To improve the efficiency in the continuous work of check and repair of girders of a high level bridge.

A frame of a self-traveling vehicle is provided with a multi-stage extension mast, and a work base is provided in an upper part of the mast so as to form a vehicle for high lift work. The work base has plural stages of projecting scaffold to be extended and shrunken, and has a rotary mechanism to be turned around the extension mast. The projecting scaffold is provided with an extension leg part for damping the falling moment of the vehicle for high lift work.