To provide a diamond covered cutting edge capable of preventing the deterioration of sliding or cutting quality while sufficiently making the most of the wear resistance of diamond in the cutting edge for cutting or scribing a brittle material such as an optical fiber or glass substrate.

In the diamond covered cutting edge including a base material and a diamond layer covering the surface of the base material, the average thickness of the diamond layer in an edge part of the cutting edge is ≥0.5 μm and ≤8.0 μm, the diamond average particle diameter on the surface of the diamond layer is ≥0.5 μm and ≤6.0 μm and the surface of the diamond layer is not surface-smoothed after covered.