A plasma deposition apparatus includes a cathode assembly including a cathode disk and a water-coolable cathode holder supporting the cathode disk, an anode assembly including a water-coolable anode holder, a substrate mounted on the anode holder to serve as an anode, and a substrate holder mounting and supporting the substrate, and a reactor for applying a potential difference between opposing surfaces of the cathode assembly and the anode assembly under a vacuum state to form plasma of a raw gas. The cathode disk comes into thermal contact with the cathode holder using at least one of a self weight and a vacuum absorption force so as to permit thermal expansion of the cathode disk.