To provide a catalyst layer for a fuel cell, which exhibits excellent power generation performance even in the case of reducing the used amount of a catalyst. It is an electrode catalyst layer for a fuel cell comprising a catalyst, a porous carrier for supporting the above-mentioned catalyst, and a polymer electrolyte, in which a mode diameter of the pore distribution of the above-mentioned porous carrier is 4 to 20 nm, and the above-mentioned catalyst is supported in a pore with a pore diameter of 4 to 20 nm of the above-mentioned porous carrier.