An electrolyzer apparatus includes an anode tank having an anode and a cathode tank having a cathode which are provided separately from each other. The anode tank includes a feed opening for feeding electrolytic solution into the tank, an anode aeration device for feeding aeration air to the fed electrolytic solution, and a gas extraction pipe for guiding gas generated from the anode tank to outside the tank. A communication pipe allows the amount of electrolytic solution fed into the anode tank to flow into the cathode tank, and via the electrolytic solution in the communication pipe, electric conduction becomes possible between the anode and the cathode. An amount of gas generated by an electrolysis reaction inside the anode tank is discharged to the outside of the anode tank via the gas extraction pipe together with the aeration air. The electrolytic solution introduced into the cathode tank is discharged continuously.