Provided is a method with which it is possible to easily produce an electrode catalyst having excellent catalytic performance such as kinetically controlled current density. The method involves: a dispersion liquid preparation step of preparing a dispersion liquid by mixing (i) at least one type of solvent selected from the group consisting of sulfoxide compounds and amide compounds, (ii) a catalyst carrier powder constituted by a metal oxide, (iii) a platinum compound, (iv) a transition metal compound, and (v) an aromatic compound including a carboxyl group; and a loading step of heating the dispersion liquid to thereby load a platinum alloy of platinum and a transition metal on a surface of the catalyst carrier powder.