SURFACE COATED CUTTING TOOL WITH HARD COATING LAYER HAVING SUPERIOR CHIPPING RESISTANCE AND FRACTURE RESISTANCE

PROBLEM TO BE SOLVED: To provide a surface coated cutting tool with a hard coating layer exhibiting superior chipping resistance and fracture resistance in high-speed intermittent cutting.SOLUTION: In a surface coated cutting tool with a hard coating layer arranged on a surface of a base body of the tool made of a WC-based cemented carbide or a TiCN-based cermet, the hard coating layer is formed of a lower layer and an upper layer. The lower layer is a Ti compound layer: formed of one or two or more layers out of a titanium carbide layer, a titanium nitride layer, a titanium carbonitride layer, a titanium carbonate layer, and a titanium carbonitride oxide layer; and moreover, having an average total layer thickness of 3-20 μm. The upper layer is an aluminum oxide layer having an average layer thickness of 1-25 μm. The aluminum oxide layer forming the upper layer contains a plate-like growth aluminum oxide crystal phase and an amorphous aluminum oxide phase. On a surface of the upper layer, an occupancy ratio of the plate-like growth aluminum oxide crystal phases is 5-35 area%, and an amorphous aluminum oxide phases exist so as to fill clearances between the plate-like growth aluminum oxide crystal phases.