To prevent floating stones from occurring during molding by means of centrifugal force by setting the centrifugal force to be a centrifugal force at a middle speed being 8-20 times of the acceleration of gravity and the rotating time to be at most 1min.

When a molded article by means of centrifugal force is molded by using a concrete compounded with a kneading material for decreasing or preventing sludge from being generated during molding by means of centrifugal force, at first, rotation is performed by a low speed centrifugal force and then, it is rotated by a middle speed centrifugal force being 8-20 times of the acceleration of gravity for at most 1min and furthermore, it is rotated by a high speed centrifugal force to perform compacting. Therefore, it is possible to prevent floating stones from occurring during molding by centrifugal force and there exists no possibility of generating both a claim in which an auger is not penetrated into a pile, etc., and a rejected part in fume pipes.