CATION-EXCHANGE MEMBRANE, A PRODUCTION METHOD THEREOF, AND AN ELECTROLYTIC CELL UTILIZING SAME

A cation exchange membrane which shows suppressed deterioration of the strength of the membrane in the upper portion of an electrolytic cell when the membrane is employed in the electrolytic cell and used for a long term, which can perform electrolysis with good production efficiency, and which can be produced simply with low cost; its production process and; such an electrolytic cell; are provided. A cation exchange membrane to be used for an electrolytic cell, which has a laminate structure comprising a first layer containing a fluoropolymer having sulfonic groups and a second layer containing a fluoropolymer having carboxylic groups and adjacent to the first layer, and which has a rectangular shape with a constant thickness; wherein the cation exchange membrane has an attachment region along one (or each) of opposed sides of the cation exchange membrane and a main region other than the attachment region; the value of the ratio (the thickness of the second layer) / (the total thickness of the first and second layers) in the attachment region is larger than the value of the ratio in the main region. Further, its production process and an electrolytic cell to which the cation exchange membrane is attached.