In a plasma treatment system, a temperature detection section detecting a temperature of a perfusion layer of an electrically conductive solution is fixed to a treatment portion, and is located at a position to be immersed in the perfusion layer when a first electrode portion and a second electrode portion are immersed in the perfusion layer. In the plasma treatment system, a control section controls an adjustment of a temperature in a temperature adjustment unit and controls a supply volume and a suction volume of the electrically conductive solution on the basis of a detection result in the temperature detection section so that the temperature of the perfusion layer is within a target temperature range.