There is provided a plasma processing apparatus for performing plasma processing on a substrate, comprising: a processing container accommodating the substrate; an electrode to which a high-frequency power for generating plasma in the processing container is applied; a high-frequency power supply configured to apply the high-frequency power to the electrode; and a high-frequency power supply circuit configured to supply the high-frequency power from the high-frequency power supply to the electrode. The high-frequency power supply circuit comprises: a power supply path configured to supply a power from the high-frequency power supply to the electrode; and a matching device configured to match a high-frequency power supply-side impedance with a plasma-side impedance, the matching device comprising a negative impedance portion that is connected to the power supply path and realizes a negative impedance corresponding to a plasma-side impedance.