An electrode catalyst layer for a fuel cell includes a catalyst/support composite including a support and a catalyst supported thereon. The support contains a titanium oxide. The surface of the catalyst/support composite has an oxide of at least one element selected from the group consisting of niobium, tantalum, zirconium, and silicon. The ratio A2/A1 is from 0.35 to 1.70, wherein A1 is the atomic ratio of titanium on a surface of the catalyst layer and A2 is the atomic ratio of a total of niobium, tantalum, zirconium, and silicon on the surface of the catalyst layer, A1 and A2 being measured by X-ray photoelectron spectroscopy. The titanium oxide preferably has a composition TiOx (0.5 ≤ x