In a plasma processing apparatus, a ceiling electrode plate provided to face a substrate holding stage via a process space contacts and is supported by an electrode support by interposing a cooling plate, and a heat-transfer sheet is provided in a contact surface between the ceiling electrode plate and the cooling plate. The heat-transfer sheet has thermal conductivity of 0.5 to 2.0 W/m·K. The heat-transfer sheet is provided of a heat-resistant adhesive agent or a rubber including silicon, or the heat-transfer sheet is formed of a ceramic filler including oxide, nitride, or carbide. The ceramic filler of 25 to 60 volume % is contained in the heat-resistant adhesive agent or the rubber. A thickness of the heat-transfer sheet is in a range between 30 and 80 μm, and the heat-transfer sheet is not provided in a predetermined area around gas holes of the ceiling electrode plate.