PURPOSE:To prevent the thermal decomposition of powder as well as the ignition and explosion of floating powder by staying the powder on the upside of a cooled temperature-regulating heat medium circulation section without direct contact with the upside of a heated mandrel. CONSTITUTION:A heat insulation section 12a is provided in the upper part of a mandrel 15, a heat insulation section 12a is provided on the inner surface of the mandrel 15, and the heat insulation sections 12a and 12b are integrally made up. A temperature-regulating heat medium circulation section 14a is provided on the upper surface of the mandrel 15, and a heat medium circulation section 14b is provided between the through portion of the mandrel 15 and the periphery of a powder feed tube 2, and they are integrally connected with each other. Spaces 9a and 9b are formed between the heat insulation sections 12a and 12b and the heat medium circulation sections 14a and 14b in such a way as to more enhance the heat insulation effect. Since the powder 7 is insulated from the heat of the mandrel 15 and a die 1, the thermal decomposition of the powder can be prevented, and also since the powder 7 is stayed on the upside 18 of the heat medium circulation section 14a, the formation of floating powder can be suppressed.