PURPOSE: To eliminate necessity of spraying particles for increasing sticking on road surface by providing, in parallel with a wheel shaft, multiple rings between a cylindrical outer wheel of which outer side forms a tread and a wheel to increase the frictional force between the tread and the road surface.

CONSTITUTION: A ceramic coating which is large in frictional coefficient and resistant in radio activity and heat resistance is applied, in as-spray condition, onto a tread 11 of an outer wheel 1. Also the outer wheel 1 is formed cylindrically by increasing the radius of curvature of a crowning on the tread 11 as large as possible so that the contact surface of the tread 11 of the outer wheel 1 with road surface is increased. In addition, because a steel wheel is not elastic, multiple rings 3 which are low in spring rigidity are welded in radial direction between the cylindrical outer wheel 1 and a wheel 2 which forms a connection with the wheel and is provided with an inner wheel 22 so that uneven contact of the tread 11 with road surface can be avoided.