PURPOSE: To prevent the breakage of an eccentric member caused by bending moment by the arrangement such that the axis of a universal wheel comprising an eccentric member rotatably connected to a main body which is attached to a body to be supported and a wheel passes through a supporting plane, whereby the main body supports the eccentric member.

CONSTITUTION: A main body 18 is fixed to the underside of a body 12 to be supported by means of screws 20 and an eccentric member 26 is rotatably connected to the body 18 so that a wheel 31 is mounted on the member 26 to constitute a universal wheel 15. And an axis 32, which passes through the center of reaction of the wheel 31 and extends vertically, is set so as to passes through a supporting plane 33 of the body 18 which supports an axis 27. Consequently the reaction force imparted to the body 12 from a supporting body 10 is transmitted from the wheel 31 through the member 26 and the plane 33, so that bending moment is not exerted on the member 26 thereby preventing the breakage thereof.