Abstract: A plasma processing apparatus includes a plasma processing chamber, a substrate support disposed in the plasma processing chamber, an annular baffle plate disposed so as to surround the substrate support, the annular baffle plate having a plurality of openings, a first annular plate disposed below the annular baffle plate, a second annular plate disposed below the first annular plate, the second annular plate having an annular overlapping portion vertically overlapping with a part of the first annular plate, a pressure detector configured to detect a pressure in the plasma processing chamber, and at least one actuator configured to vertically move at least one of the first and second annular plates so as to change a distance between the first annular plate and the second annular plate based on the detected pressure.