ELECTROCHEMICAL ELEMENT

The purpose of the present invention is to provide an electrochemical element that can withstand prolonged use, with little damage or degradation due to the pressure of hydrogen gas generated, even when used for prolonged periods of time. This electrochemical element is equipped with a hydrogen-releasing film and has a laminated body in which an anode and a cathode are laminated with a separator interposed therebetween. The hydrogen-releasing film contains a metal layer, the separator contains pulp, and the total sulfur component content in the separator is 400 ppm or less as determined by quartz tube combustion gas absorption ion chromatography.