An electrode, a method of producing the same, and a fuel cell including the electrode are disclosed. The electrode includes: a support; and a catalyst layer formed on the support, the catalyst layer includes: a support catalyst; and a proton conductor having an amorphous phase greater than about 60% by weight. The proton conductor includes: at least one material from the group of B.sub.2O.sub.3, ZrO.sub.2, SiO.sub.2, WO.sub.3, and MoO.sub.3; and P.sub.2O.sub.5, the proton conductor being 0.5-60 parts by weight where the support catalyst is 100 parts by weight. The proton conductor can be synthesized at a low enough temperature so that it can be applied to the support with catalyst particles to form a catalyst layer. The coated proton conductor is in a solid state so the fuel cell is stable over time and it does not obstruct a fuel gas so that the catalyst can be more efficiently used.