The diamond coated tool of the present invention is a diamond coated tool including a base material and a diamond layer coating a surface of the base material, and characterized in that the surface of the base material has an arithmetic average roughness Ra of not less than 0.1 μm and not more than 10 μm and an average length of roughness profile elements RSm of not less than 3.1 μm and not more than 5.4 μm, and that the diamond layer has a plurality of cavities at a portion bordering on the base material.