A treatment liquid production device includes a first tank a first plasma generating device that includes a first pair of electrodes and a first power supply, the first power supply applying a voltage between the first pair of electrodes, the first plasma generating device generating plasma in a liquid in the first tank a second tank a second plasma generating device that includes a second pair of electrodes and a second power supply, the second power supply applying a voltage between the second pair of electrodes, the second plasma generating device generating plasma in a liquid in the second tank and a controller operative to produce a first treatment liquid having a high initial oxidizing power during a first period and a second treatment liquid having a high remaining oxidizing power during a second period which is longer than the first period.
