A plasma processing apparatus including a processing vessel 10 in which a plasma process is performed and a plasma generation antenna 20 having a shower plate 100 which supplies a first gas and a second gas into the processing vessel 10, performs the plasma process on a substrate with plasma generated by a surface wave formed on a surface of the shower plate 100 through a supply of a microwave. The shower plate 100 has multiple gas holes 133 configured to supply the first gas into the processing vessel 10 and multiple supply nozzles 160 configured to supply the second gas into the processing vessel 10, and the supply nozzles 160 are protruded vertically downwards from a bottom surface of the shower plate 100 and are provided at different positions from the gas holes 133.