PCBN tools are used worldwide for machining of hardened steel parts in automotive industries. Because cutting by PCBN tools has many advantages, which are high-precision, highefficiency, high-flexibility and low total machining cost, compared with conventional grinding methods. But in heavy interrupted cutting of hardened steel, the tool life is not so stable by sudden breakage of the cutting edge, and total cost of cutting by PCBN is not so economical compared to the grinding. So the conventional grinding is still main process in such applications. Recently, demand for decreasing machining cost has grown in heavy interrupted cutting and much tougher PCBN material is required. To solve this problem, new PCBN has been developed. New PCBN has very fine and homogeneous microstructure to increase the toughness of sintered body that it provides a reliable tool life for heavy interrupted cutting. The features and cutting performances of new PCBN are described in this report.