A plasma therapy apparatus capable of acquiring information on ozone concentration. An active gas irradiation device (plasma treatment device) is provided with a plasma generating unit for generating plasma, and an injection gas containing one or both of the plasma and active gas generated by the plasma. And an irradiator 10 having a nozzle that discharges toward the object, and measures at least one of the ozone concentration in the propellant gas, the ozone concentration in the vicinity of the irradiation object, and the ozone concentration in the working environment. And an ozone concentration measuring device 80 that performs the measurement. [Selection diagram] Fig. 1【課題】オゾン濃度の情報を取得できるプラズマ式治療装置。【解決手段】活性ガス照射装置１００（プラズマ式治療装置）は、プラズマが発生するプラズマ発生部と、前記プラズマ及び前記プラズマによって発生した活性ガスのいずれか一方又は両方を含む噴射ガスを被照射物に向かって吐出するノズルと、を有する照射器具１０と、前記噴射ガス中のオゾン濃度、前記被照射物の近傍におけるオゾン濃度、及び、作業環境におけるオゾン濃度の少なくとも１つ以上のオゾン濃度を測定するオゾン濃度測定器８０と、を備える。【選択図】図１
