PURPOSE: To simplify a power circuit and to reduce power loss by separately supplying the purified water from a water purifier into the anode side and cathode side in an electrolytic cell and controlling a flow switch provided to each branch passage to regulate pH.

CONSTITUTION: A current is applied between the electrodes 105 and 106 of an electrolytic cell 8 through a regulator 1, an inversion relay 102 and a current sensor 103 to start electrolysis, and alkaline ionized water and acidic water are respectively discharged from intake pipes 9 and 10. At this time, the pH of the alkaline ionized water is measured by a pH sensor 107, sent to a CPU 13 and compared with the set pH. A stepping motor is driven to adjust the opening degree of the flow switches 5 and 4 provided to the branch pipes 6 and 7 on the anode side and cathode side connected to a water pipe 2 based on the compared result, and the flow switches 11 and 12 furnished to the intake pipes 9 and 10 are controlled to adjust the amt. of water to be supplied to the electrolytic cell 8.