Inconel 718, a super-heat-resisting alloy, is difficult to cut, increasing the need for more efficient cutting. Tool wear in commonly used coated cemented carbide tools is identified clearly based on observations during cutting experiments. Tool life in interrupted cutting is shorter than during continuous cutting because the built-up edge is removed, causing the coating film to flake when the tool parts from the workpiece during interrupted cutting. Cutting that gradually reducing undeformed chip thickness at cutting end prevents the separation of built-up edges and reduces tool wear during interrupted cutting.