PURPOSE: To utilize efficiently water, and to operate stably a cathode by returning the water accumulated in the cathodic gas chamber again to an anodic water chamber in a titled apparatus using an ion-exchange membrane as an electrolyte.

CONSTITUTION: The main body 1 of a titled apparatus is formed of an ion- exchange membrane 2, a cathode and an anode 3 and 4, collector bodies of the electrodes 5 and 6, a cathodic gas chamber 7, an anodic water chamber 8, terminal plates of the cathode and the anode 9 and 10, a cell frame 11, and a gas introducing and a gas discharge port 12 and 13. The water is supplied into the chamber 8 from a water tank 14 and an O2-contg. gas from the inlet 12. A deoxidizing reaction takes place at the cathode 3 by passing a DC current between the plates 9 and 10. The deoxidized remaining gas is discharged from a discharge port 16 through a water storage chamber 15 which is provided either to a port of the chamber 7 or to the discharge part of the gas, and the water formed at the cathode 3 and the water moving from the anode side 4 to the cathode side 3 are stored in the chamber 15. Meanwhile, the O2 passes through the chamber 8 as bubbles, and is discharged from the outlet 13. The water in the chamber 15 is returned directly or through the tank 14 by a pump 17, and supplied into the chamber 8.