Diamond thin films have been grown epitaxially on high‐pressure synthesized cubic boron nitride (c‐BN) particles by using dc plasma chemical vapor deposition. At the early growth stage of the film onc‐BN{111} surfaces, the island structure is observed and the number density of islands is about 1011cm−2. The growth and the coalescence of islands are also found by scanning electron microscopy observation. The continuous film is obtained at the thickness of about 2000 A˚ and the surface of the film is rather smooth. The Raman peak of the epitaxial diamond film shows the shift toward the lower wave number due to the tensile stress involved in the film.