In a plasma processing apparatus including a plasma processing chamber disposed in a vacuum chamber, a sample stage disposed in the plasma processing chamber and on which a sample is placed, in the vacuum chamber, a second shower plate disposed above the sample stage, a first shower plate disposed above the second shower plate, and a dielectric window disposed above the first shower plate, first gas is supplied from a first gas supply unit to a space between the dielectric window and the first shower plate, and second gas is supplied from a second gas supply unit to a space between the first shower plate and the second shower plate.