Abstract: An apparatus for producing electrolytic water in which the yielded electrolytic water does not suffer quality deterioration caused by chemical species, e.g., hydrogen ions, moving to the counter-electrode chamber. A diaphragm 4 of a two-chamber type electrolytic cell comprises two or more ion-exchange membranes 3, and a noble-metal layer 2 or another layer may be formed in the diaphragm. Use of the ion-exchange membranes produces an enhanced physical screening effect, while formation of the noble-metal layer produces catalytic effect to decompose chemical species. Both the ion-exchange membranes and the anode-metal layer are effective in diminishing the movement of chemical species to the counter-electrode chamber.