PURPOSE: To obtain a forging die having durability for maintaining its accuracy for a long period of time, by specifying the quality of material of a die insert of the center part of a die, an intermediate ring of its outside circumference and also a reinforcing ring of its outside circumference, respectively.

CONSTITUTION: A die consists of a die insert 10 of the center part, an intermediate ring 11 of the intermediate part and a reinforcing ring 12 of the outermost part, and they are clamped firmly to each other by means of shrinkage fit, expansion fit, press fit, etc. As for the quality of material of the die insert 10 of the center part, a new ceramic material having high heat resistance, such as single crystal sapphire, a silicon nitride sintered body, etc. is used. As for the quality of material of the intermediate ring 11, a tungsten carbide sintered body having a high Young's modulus is used, and also as for the quality of material of the reinforcing ring 12, alloy steel to which quenching and tempering are performed is used.