An oxide composite particle of the present invention is composed of at least one fine gold particle contained in a matrix of an oxide particle or at least one fine gold particle supported fixedly on the surface of an oxide particle, and absorbs a visible light having a specific wavelength. A phosphor of the invention has a thin film which is composed of such oxide composite particles on the surface of a phosphor particle of red or the like. The phosphor can be obtained by mixing phosphor particles into a dispersion of gold colloid/oxide composite particles, agitating the resultant mixture, and taking out the precipitated phosphor particles, followed by drying. Further, in a color filter of the invention, a filter layer of at least one color formed on an inner surface of a panel is a thin film composed of the above-described oxide composite particles. This provides a phosphor or color filter which is excellent in optical characteristics, heat resistance and non-toxicity and never interferes with the irradiation of a photoresist with ultraviolet rays, and realizes a color display which exhibits good luminous chromaticity and is excellent in brightness and contrast.