Liquid processing apparatus

A liquid processing apparatus comprising:

• a cylindrical processing tank of which one end portion is closed and which has a circular cross-sectional shape;
• a liquid introduction port that is disposed on a first end side of the processing tank, causes a liquid to swirl in the processing tank by introducing the liquid into the processing tank in a tangential direction of the processing tank, and generates a gas phase in a swirling flow of the liquid;
• a discharge portion that is disposed at a second end of the processing tank and discharges the liquid introduced from the liquid introduction port;
• a rod-shaped first electrode that is disposed at the first end on a central axis of the processing tank;
• a second electrode that is disposed so as to be exposed to the discharge portion of the processing tank;
• and
• a power supply that applies a voltage between the first electrode and the second electrode to generate plasma in the gas phase between the first electrode and the second electrode.