A plasma processing method for processing a sample by reducing a pressure within a processing chamber, including mounting the sample on a sample holder disposed in the processing chamber, and processing using a plasma generated in the processing chamber above the sample holder while supplying a gas for heat transfer to a space between a surface of the sample holder having the sample mounted thereon and a rear surface of the sample. The sample holder has a plurality of substantially ring-shaped depressed portions at the surface where the sample is mounted. A pressure in a space between the depressed portions arranged at a central portion of the sample holder with respect to outer circumferential portion and the sample is set to be lower than a pressure in a space between the depressed portions at the outer circumferential portion and the sample.