Surface coated cutting tool

A surface coated cutting tool comprising a substrate and a coating segment on the surface of the substrate, wherein

• (a) the coating segment comprises an A layer, a B layer, and a C layer, in contact with each other in order from the surface of the substrate to the surface of the tool, and the sum of the average thicknesses of these three layers ranges from 0.7 to 21.0 μm,
• (b) the A layer has an average thickness in a range of 0.1 to 2.0 μm and contains nitride or carbide of Ti,
• (c) the B layer has an average thickness in a range of 0.1 to 0.5 μm, has an average composition represented by (AlXBTi1-XB)(CYBN1-YB) (where 0.80≤XB≤0.95 and 0.00≤YB<0.05), and contains at least 30 area % crystal grains having a wurtzite-type hexagonal crystal structure and the balance being crystal grains having a NaCl-type face-centered cubic crystal structure in the cross-section of the B layer, and
• (d) the C layer has an average thickness in a range of 0.5 to 20.0 μm, has an average composition represented by (AlXCTi1-XC)(CYCN1-YC) (where 0.65≤XC≤0.90 and 0.00≤YC<0.05), and contains 5 to 25 area % crystal grains having a wurtzite-type hexagonal crystal structure and the balance being crystal grains having a NaCl type face-centered cubic crystal structure in the cross-section of the C layer.