A plasma processing apparatus for providing plasma processing to an object placed inside a processing chamber includes a vacuum chamber, a process gas feeder feeding gas into the vacuum chamber, a wafer electrode disposed within the vacuum chamber for mounting the object, a wafer bias power generator supplying bias voltage to the wafer electrode, and a plasma generator for generating plasma within the vacuum chamber. The wafer bias power generator includes a clip circuit for clipping either a positive-side voltage or a negative-side voltage to a predetermined voltage.