A plasma processing apparatus performs plasma processing on a substrate held by a carrier. The carrier includes a frame disposed around the substrate and a holding sheet which holds the substrate and the frame. The plasma processing apparatus includes: a chamber; a stage which is disposed within the chamber and has an upper surface on which the carrier is mounted; a gas hole which is provided at a position of the upper surface opposing a bottom surface of the frame and through which cooling gas is supplied between the stage and the carrier; and a plasma exciting unit which generates plasma within the chamber.