Plasma processing apparatus

The plasma processing apparatus includes: a processing chamber having a dielectric plate thereabove through which microwaves pass and performing plasma processing on a sample; a high-frequency power supply for supplying high-frequency power of the microwaves; a cavity resonator that resonates microwaves transmitted from the high-frequency power source via a waveguide tube and is disposed above the dielectric plate; and a magnetic field forming mechanism for forming a magnetic field in the processing chamber, the plasma processing apparatus further comprising: an annular conductor disposed inside the cavity resonator; and a circular conductor disposed inside the cavity resonator and disposed at an opening in the center of the annular conductor. 等离子处理装置具备：在上方具备微波所透过的电介质板且对样品进行等离子处理的处理室；供给所述微波的高频电力的高频电源；使从所述高频电源经由波导管传输的微波谐振且配置于所述电介质板的上方的空腔谐振器；和在所述处理室内形成磁场的磁场形成机构，在该等离子处理装置中，还具备：配置于所述空腔谐振器的内部的环状导体；和配置于所述空腔谐振器的内部且配置于所述环状导体的中央的开口的圆形导体。