The present invention provides a diamond coated tool (10) which is resistant to exfoliation at an interface between a base material (1) and a diamond layer (3). The diamond coated tool (10) of the present invention is a diamond coated tool (10) including a base material (1) and a diamond layer (3) coating a surface of the base material (1), and characterized in that the surface of the base material (1) 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 1 µm and not more than 100 µm, and that the diamond layer (3) has a plurality of cavities (2) extending from a portion bordering on the base material (1) in a crystal growth direction.