There is provided a catalyst for a fuel electrode of a solid polymer fuel cell, wherein the catalyst comprises fine precious metal particles loaded on a support composed of an electrically conductive material, and wherein the weight ratio of the fine precious metal particles and the support composed of an electrically conductive material (fine precious metal particles:electrically conductive material) is 60:40 to 95:5; and the fine precious metal particles satisfy the following conditions (a) to (c): (a) the fine precious metal particles contain platinum and ruthenium, and the mixing ratio thereof (platinum:ruthenium) is within a range between 1:1 and 1:3 in terms of molar ratio; (b) the fine precious metal particles have an average particle diameter of 3 to 10 nm; and (c) the fine precious metal particles contain oxygen, and the weight ratio of the fine precious metal particles and oxygen (fine precious metal particles:oxygen) is 86:14 to 96:4.