A supported platinum catalyst having a high ratio of a diffraction peak intensity of a Pt (220) plane and having excellent oxidation resistance, obtained by a simple production method without using a polymer. The supported platinum catalyst includes a carbon support and platinum fine particles supported on the carbon support, the platinum fine particles being such that a ratio of a diffraction peak intensity of a (220) plane with respect to a total of diffraction peak intensities of a (111) plane, a (200) plane, and the (220) plane by X-ray diffraction is not less than 0.128.