Changing wall thickness in the axial direction is effective in lightening of industrial parts. Aluminum tubes are formed by conventional extrusion process, therefore wall thickness is constant in the axial direction. A tapered mandrel is controlled in the same direction of ram or in the opposite direction of ram and at the same time extruding is found to be useful for changing thickness axial direction. Therefore, the authors have invented, designed and made a new prototype extrusion machine that can control the inside diameter of circular tubes. The possibility of controlling the inside diameter extrusion method is made clear by this paper.