PURPOSE: To optionally set an electrolytic level and to improve efficiency by using a semicycle selection zero cross SCR ON/OFF control system in the power source of an ionized water generator.

CONSTITUTION: The AC input to the coil (a) of a power source transformer is rectified by a mixed bridge of SCRs 1 and 2 and diodes D1 and 2 and smoothly outputted by a smoothing capacitor 12 by this power circuit. The AC input from a coil (b) is zero-cross-detected by a comparator 10, and the SCRs 1 and 2 are triggered through a pulse transformer 5 by the SCR ON/OFF voltage setting signal from a CPU 13 for designating and selecting for each half wave in synchronization with the zero cross to obtain an electrolytic power source of the optionally set electrolytic level. A voltage transducing circuit 7 or the overcurrent detecting voltage on both sides of a source resistance R2 of Q2 is judged by a comparator 8, and the generator is protected for the overcurrent corresponding to the electrolytic level.