To prevent a sterilization effect from being lowered with time after electrolysis by electrolyzing a fixed quantity of an electrolyte having a fixed concentration to generate an acidic electrolytic water and adding an inorganic acid buffer solution therein to adjust a hydrogen ion concentration.
Acidic electrolytic water 2 obtained by electrolyzing in an electrolytic cell 11 is selected by a four-way valve 17 and an inorganic acid buffer solution such as an acetic acid buffer solution, a hydrochloric acid buffer solution or a phosphoric acid buffer solution is ejected thereinto to adjust a hydrogen ion concentration. The inorganic acid buffer solution having a characteristic of adjusting a hydrogen ion concentration without decomposing hydrochloric acid and changing a sterilization effect is used and the concentration is adjusted in accordance with the hydrogen ion concentration to be adjusted. As the result, the change of the hydrochloric acid concentration in the acidic electrolytic water with time is suppressed and the lowering of the sterilization effect with time is prevented.
FURUMI HIDETO
ARATA YOJI
