Abstract: An electrolytic process employing a diaphragm of a size of at least 1 cm in length in at least two directions, the diaphragm comprising a diaphragm base composed of fibers of fibrous structure containing inorganic fibers and a binder containing a fluorine-containing resin, the fluorine-containing resin being present in an amount of 0.5 - 60% by weight based on the weight of the diaphragm.