Recently, PCBN cutting tools have received a great deal of attention as a material for cutting tools to achieve high performance machining of Inconel 718. In this study, turning and orthogonal cutting experiments on Inconel 718 employing two types of PCBN cutting tool were conducted in order to evaluate the tool life and identify the wear mechanisms, at a wide range of cutting speeds. The results of the experiments indicated that the tool life and wear behavior of the PCBN cutting tools significantly depend on the cutting speed and material structures, and a PCBN tool, which has a low CBN content with TiN-based ceramic binder, shows excellent wear resistance in high speed machining of Inconel 718.