When a titanium-containing gas and an oxidizing gas, or a silicon-containing gas and a nitriding gas, are alternately supplied from a gas supplier and radio frequency power is supplied to each of a first electrode and a second electrode from a power supply, parallel to the supply of the oxidizing gas or the nitriding gas, so as to generate plasma and to perform a film formation, a magnitude of the radio frequency power to be supplied to each of the first electrode and the second electrode is controlled.