Provided is a coated cutting tool in which a surface of a substrate is coated with a hard coating film. The hard coating film includes: a layer (A) disposed on the surface of the substrate, and having a face-centered cubic lattice structure, in which the total content ratio of W and Ti is at least 85 atomic %, and which contains W as the most abundant element and Ti as the next most abundant element among metal (including metalloid) elements; and a layer (B) disposed on the layer (A) and having a face-centered cubic lattice structure, which is composed of nitrides or carbonitrides containing Al, Cr, and Si, and in which, among metal (including metalloid) elements, the Al content ratio is at least 50 atomic %, the total content ratio of Al and Cr is at least 85 atomic %, and the Si content ratio is 4 to 15 atomic %.

A cutting tool, including a silicon nitride (Si.sub.3N.sub.4) ceramic substrate, and a diamond film coated on the surface of the Si.sub.3N.sub.4 ceramic substrate. The diamond film has a thickness of 7-12 μm. The cutting tool includes a tool nose, a blade, and a handle. The blade has a rake angle γ of 5-15°, a clearance angle α of 10-14°, and a helix angle of 15-45°. The blade includes four cutting edges.

Provided is a coated cutting tool in which a surface of a substrate is coated with a hard coating film. The hard coating film includes: a layer (A) disposed on the surface of the substrate, and having a face-centered cubic lattice structure, in which the total content ratio of W and Ti is at least 85 atomic %, and which contains W as the most abundant element and Ti as the next most abundant element among metal (including metalloid) elements; and a layer (B) disposed on the layer (A) and having a face-centered cubic lattice structure, which is composed of nitrides or carbonitrides containing Al, Cr, and Si, and in which, among metal (including metalloid) elements, the Al content ratio is at least 50 atomic %, the total content ratio of Al and Cr is at least 85 atomic %, and the Si content ratio is 4 to 15 atomic %.