PURPOSE: To provide industrial material having high hardness and high strength, by constituting bonded structure of three dimensional network by use of diamond powder, hard carbide powder, low melting alloy powder such as Co alloy, and high melting ,metal powder.

CONSTITUTION: Following four kinds of raw materials are used: (1) diamond powder, (2) hard carbide powder such as WC etc., (3) a low melting alloy powder selected from the group consistng of Fe alloy, Co alloy, Ni alloy, Mn alloy, Cr alloy, and Zn alloy, (4) a high melting metal powder selected from the group consisting of Ni, Co, Fe. The mixed raw material composed of the four kinds of material is treated in the first step at a temp. not higher than 1,100°C, and at a press. not lower than 100 kg/cm2 for up to 10 min. to fill up the molten low melting alloy powder among the diamond powder, the hard carbide powder, and the high melting metal powder. Thereafter, in the second step, the mixture is treated under temp. and press. conditions where diamond crystals are stable in order to give three dimensional net work to the fused solid made from the low melting alloy bonded to the diamond particles and the high melting alloy bonded to the WC particles.