“Carbonic Acid Hypochlorite Generation System” is a functional water production system that adjusts the pH of sodium hypochlorite to optimum weakly acidic by using carbonated water. The combination of safety and stability is the biggest feature. The generated carbonic acid hypochlorite has high bactericidal activity even at low concentration even for a short time. Since the pH does not drop to 5.0 or less due to the buffering action of carbonic acid gas, chlorine gas is not generated when mixing sodium hypochlorite. In addition, a generation method that stabilizes the dissolution rate of carbon dioxide gas is adopted.