PURPOSE: To contrive an improvement in dimensional accuracy of the inside and outside diameters of a molded body and to contrive an improvement in a coaxial degree by eliminating a warp at the same time, by a method wherein a core forming an annular extrusion flow path is formed along the shaft center and a gas passage for cooling opened at the tip is provided.

CONSTITUTION: A mold is provided with a hollow outside ring 2 and hollow core 4 inserted within the ring 2. An annular extrusion flow path 5 is formed between the outside ring 2 and core 4, and the core 4 possesses a cooling gas passage 6 opened at the tip. A ceramics molded body extruded through a mold as shown by a dotted line is cooled from an inner circumferential side of the molded body at the tip part of the core by air flowing down into the gas passage 6 through the tip of the core 4 at a larger cooling effect than that of an outer circumferential side. Therefore, cooling and solidification progress from not only the outer circumferential side but also the inner circumferential side, in the ceramics molded body. With this construction, as the inner circumferential part is cooled and solidified quickly not to mention the outer circumferential part, in the ceramics molded body, favorable dimensional accuracy can be obtained on both the outer and inner circumferential parts.