PURPOSE: To obtain a metallic die which is excellent in accuracy and durability by repeating a simple means, by filling the inside of a recessed space of a shell with a specified mixture, and solidifying it, prior to backup of a hard metallic shell.

CONSTITUTION: A metallic layer 3 is formed by surrounding the first model 1 by a steel frame 2, and spraying a low-temperature molten metal to both its surface and circumference at a normal temperature. Subsequently, an inversion die 5 is obtained by releasing the model 1, and the second model 7 is obtained by pouring a molten liquid of a low-melting point alloy into a recessed space 6 on this die 5. The model 7 is fixed onto a surface plate 8 surrounded by a steel frame 10, and a high-melting point metal is sprayed at a normal temperature, by which a spray metallic layer 11 is formed. The metallic layer 11 is detached from the frame 10, installed to a mold base 10', and a recessed space 11' of a shell 11 fixed to the mold base 10' is filled with a mixture of sand and soda silicate, by which a solid sand lump 12 is formed. A backup 13 is executed by spraying a metal to the rear side space of the shell 11. Subsequently, the solid sand lump 12in the shell 11 is removed, and the recessed surface of the shell 11 is finished, by which a metallic die is completed.