A plasma processing apparatus includes a container; a stage disposed in the container and including an electrode; a plasma source that generates plasma in the container; a bias power supply that periodically supplies a pulsed negative DC voltage to the electrode; an edge ring disposed to surround a substrate placed on the stage; and a DC power supply that supplies a DC voltage to the edge ring. The DC power supply supplies a first DC voltage in a first time period when the pulsed negative DC voltage is not supplied to the electrode, and supplies a second DC voltage in a second time period when the pulsed negative DC voltage is supplied to the electrode.