1. A sound processing device comprising: a time-frequency analysis unit which generates a time-frequency plane from a sound signal through time-frequency analysis; a region characteristic amount extraction unit which, for a plurality of partial region pairs which is defined on the time-frequency plane and of which at least either of shapes of two partial regions or positions of the two partial regions differ from one another, extracts a region characteristic amount from each partial region; a sound identifier generation unit which generates a sound identifier using a difference value of the region characteristic amounts extracted from each partial region, wherein the sound identifier generation unit comprises a memory unit which memorizes a comparison and a quantization method by correlating them to the partial region pair, and performs comparison and quantization by the comparison and the quantization method corresponding to the partial region pair; and a processor configured to perform at least one function of at least one of the time-frequency analysis unit, the region characteristic amount extraction unit, and the sound identifier generation unit.