Abstract: The tubular die of a centrifugal casting device of GNo.30 or above is employed suitably and powder is introduced while rotating, and an outer tubular body composed of that powder is provided. Subsequently, molten is introduced to the inner circumferential wall side of the outer tubular body while sustaining rotation of the tubular die thus forming an inner tubular body. The outer tubular body functions as a cooling metal (chiller) when the molten is cooled and solidified. In place of the outer tubular body composed of the powder, molten may be used for forming an outer tubular body or an outer tubular molding molded previously into tubular shape may be employed.