PURPOSE: To efficiently heat a substrate and to facilitate the maintenance and inspection of a heater by arranging the heater on the outside of the window provided across from the RF electrode of a substrate holder, and forming the window with a material capable of transmitting the heat ray of the heater.

CONSTITUTION: The RF electrode 2 is arranged in reaction chamber 1 through an earth shield 3, and the substrate holder 4 for holding the substrate 5 is arranged in opposition to the electrode 2. A voltage is impressed on the RF electrode 2 to produce plasma. The substrate holder 4 and the substrate 5 are heated by the heater 8 furnished with a heat reflecting plate 9 and arranged on the outside of the reaction chamber 1 in opposition to the window 6 through the window 6 provided across from the RF electrode 2 with the substrate holder 4 in between, and a film is formed on the substrate 5. In the plasma CVD device, the window 6 is formed with the material capable of transmitting the head ray of the heater 8. By this method, the thermal decomposition of the gas is prevented, a film is efficiently formed, and the maintenance and inspection of the heater 8 can be easily carried out without turning off the vacuum in the reaction chamber 1.