The present disclosure relates to a producing method for oxynitride or nitride phosphor powders which can be used in displays such as vacuum fluorescent display (VFD), field emission display (FED) and LED display devices, or in lighting devices such as cold cathode fluorescent lamps (CCFL) and LED lamps, or in light-emitting apparatuses such as back-lights, wherein the producing method for phosphor powders comprises the step of subjecting part or all of a metal oxide to nitriding by calcining in an atmosphere containing nitrogen, using a fine carbon substance.