NOVELTY - Catalyst particle comprises an inner particle containing on at least a surface a first oxide having oxygen defects, and an outermost layer that contains platinum and covers the inner particle.    USE - The catalyst particle is useful in a carbon-supported catalyst particle for a fuel cell catalyst (claimed).    ADVANTAGE - The catalyst particle provides fuel cell catalysts with high catalytic activity.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) preparing the catalyst particle, comprising preparing a dispersion of particles composed of a second oxide i.e. free of oxygen defects, preparing a dispersion of platinum ions, mixing together the dispersion of particles composed of the second oxide and the dispersion of platinum ions, reducing at least the surfaces of the particles composed of the second oxide to a first oxide having oxygen defects, and fonning on the first oxide an outermost layer containing platinum formed by reduction of the platinum ions, and heating the mixture after forming the outermost layer on the first oxide;    (2) a carbon-supported catalyst particle comprising the catalyst particle, and a carbon support that supports the catalyst particle; and    (3) manufacturing the carbon-supported catalyst particles, comprising, either when a reducing agent is used to pre-reduce particles composed of at least the second oxide, mixing the carbon support either before additionally mixing the reducing agent into the mixture of the dispersion of reversed micelles containing particles composed of the second oxide with the dispersion of reversed micelles containing platinum ion or after additionally mixing the reducing agent into the mixture, or when the platinum ions are reduced by light irradiation, additionally mixing a sacrificial reagent into the mixture of the dispersion of particles composed of the second oxide with the dispersion of platinum ions, and irradiating the mixture with light, following which a carbon support is additionally mixed into the light-irradiated mixture.