PURPOSE: To prevent generation of poisoning substance and hydrophilic substance by immersing a thin film of electrode catalyst layer in water, baking the thin film at the temperature, at which fluorine resin is melted, to bond the electrode catalyst layer on an electrode substrate.

CONSTITUTION: Fine catalyst particles 7 in which fine particles 1 of noble metal such as platinum is supported in a catalyst support 2 are dispersed in surface active agent aqueous solution. PTFE dispersion (in which fine PTFE particles 3 are dispersed) is added to the catalyst particle dispersion to prepare ink-like paste. Isopropyl alcohol is added to the paste to coagulate the fine particles 7 and fine fluorine particles 3, and paint-like paste is obtained. The paint-like paste is applied to a carbon electrode 4, to which water repellent treatment is applied with PTFE dispersion, to form a film, then dried until the residual content of moisture and isopropyl alcohol are 20∼30% to obtain the coating film of an electrode catalyst layer 5. The coating film is pressed on the carbon electrode substrate 4 by a presser.