PURPOSE: To obtain the good double-collared pipe by providing the second collar through casting further to the single-collared pipe having been once been centrifugally cast.

CONSTITUTION: First, the other end of a centrifugally cast pipe 2 having a single collar 1 is installed on a metal mold 4a serving also as a molding board. Next, a pipe fixing mold 6 and an inside core 5 are set with cylinders C1, C2, C5, after which a peripheral metal mold 4b is fixed by cylinders C6, C7. Thence, the metal mold 4 and pipe 2 are heated, after which coat is applied on the inside surface of the metal mold 4 and molten metal is poured, thence the upper metal mold 4C is put on and pressing pressure is applied with the cylinders C3, C4 to let the molten metal solidify.