A plasma processing device that includes a processing chamber which is disposed in a vacuum vessel and is decompressed internally, a sample stage which is disposed in the processing chamber and on which a sample of a process target is disposed and held, and a plasma formation unit which forms plasma using process gas and processes the sample using the plasma, and the plasma processing device includes: a dielectric film which is disposed on a metallic base configuring the sample stage and connected to a ground and includes a film-like electrode supplied with high-frequency power internally; a plurality of elements which are disposed in a space in the base and have a heat generation or cooling function; and a feeding path which supplies power to the plurality of elements, wherein a filter to suppress a high frequency is not provided on the feeding path.