PURPOSE: To improve cooling efficiency while also increasing a cooling rate when an injection molding die is manufactured.

CONSTITUTION: A model 2 is fixed onto a base in a sealable vessel 1, a pipe 3 for cooling is wound around the model 2, and the side faces of the periphery of the model 2 are covered with a cylindrical partition wall 4. The partition wall 4 is fastened onto the base of the vessel 1, and the inside of the partition wall 4 is filled with a metal having excellent thermal conductivity such as steel while being vibrated in order from coarse aggregate to fine aggregate as aggregate 5. Filling is completed, the outside of the partition wall 4 is filled with a material 6 such as rock having small thermal conductivity while being vibrated in order from a coarse material to a fine material in the same manner as the aggregate 5, and a binding material 7 such as phenol resin is dropped from the top faces of the aggregate 5 and the material 6 filled. The inside of the vessel 1 is hermetically sealed, and evacuated and pressed, the binding material 7 is cured, and the model 2 is mold-released.