Abstract: A method for producing an electrochemical device which exhibits improved output performance and improved durability in thermal, chemical, and mechanical is provided. The electrochemical device includes a first electrode, a second electrode, and an ion exchange membrane held between the two electrodes. The method includes forming a catalyst layer containing a catalytic substance such as platinum and polyvinylidene fluoride and attaching ion exchange groups to the polyvinylidene fluoride in the catalyst layer. The resulting catalyst layer containing ion exchange groups is used for at least either of the first and second electrodes.