A fuel cell electrode catalyst layer (13) of the preset invention includes: a catalyst (131b); a support (131a) that supports the catalyst; and two or more proton-conductive materials (133) different in dry mass value per mole of a proton-donating group, the proton-conductive materials being in contact with at least a part of the catalyst and at least a part of the support. Then, a proton-conductive material in which a dry mass value per mole of the proton-donating group is highest among the proton-conductive materials is in contact with at least a part of the catalyst, and has a largest contact ratio with a surface of the catalyst.