A multiple vertical diaphragm type electrolytic cell which is fitted with a plurality of gas-bubble guiding partition plates and/or in a style of up-and-down stages to the confront surfaces of electrodes and/or in every anode chamber and/or cathode chamber so as to form a perpendicular gas-bubble passageway at the vertical central plane position of said electrode chamber; wherein the gas-bubble guiding plates incline upwards toward the gas-bubble passageway. The guiding plates are constructed of heat-resistant synthetic resin and are slightly separated from the walls of the electrodes.