A method of manufacturing a highly crystallized phosphor powder, comprising: making a raw material solution containing metal elements and/or semimetal elements that will be constituents of the phosphor into fine liquid droplets, subjecting the liquid droplets to decomposition by heating at a temperature of 500 to 1800.degree. C. to produce hollow precursor particles and/or porous precursor particles, heating the precursor particles to crystallize the precursor particles while maintaining the hollow or porous form, and grinding the crystallized particles down to a predetermined particle size. The obtained phosphor powder is a high luminance inorganic phosphor powder that is extremely fine, and yet has few defects on the surface of or inside the powder, and hence has excellent crystallinity and light emission characteristics, and provides a phosphor composition useful for producing a phosphor layer with high coverage and high luminance of light emission.