PURPOSE: To produce a diamond sintered compact at a low cost by mixing Ti coated diamond powder with Co based heat resistant alloy powder in a specified ratio and forming a diamond bonded sintered structure by hot pressing at a low temp. under a low pressure.

CONSTITUTION: A powdery mixture of 97-70wt.% Ti coated diamond powder with 3-30wt.% Co based heat resistant alloy powder is hot-pressed at 950-1100°C sintering temp. under 1000-3000kgf/cm2 sintering pressure. By this hot pressing, many Ti coating films and the Co based heat resistant alloy powder sinter to form a Ti based sintered structure, and the same time, a sintering aid based sintered structure forms the Ti based sintered structures and a composite sintered structure. This composite sintered structure bonds to the separate diamond particles by sintering through Ti coating films sintered on the separate diamond particles as media to forma diamond bonded sintered structure.