A diamond heat sink is disclosed in this invention. The diamond heat sink has a support layer consisting of substantially undoped vapor phase synthetic diamond, a heat sensitive layer consisting of doped vapor phase synthetic diamond formed on the surface of the support layer; an insulation layer consisting of substantially undoped vapor phase synthetic diamond formed on a predetermined region of the heat sensitive layer; and an electrode formed on the heat sensitive layer. The electrode typically consists of a metal, preferably Ti/Mo/Au or Ti/Pt/Au. The diamond heat sink of the present invention may further include a highly-doped layer for creating Ohmic contacts with the metal electrode, which is made of the vapor phase synthetic diamond having high impurity levels, and which is disposed between the metal electrode and the heat sensitive layer.