The encoding efficiency of an encoder is improved by positively combining a plurality of kinds of encoding methods. A first encoder (5) encodes the result of judgement of whether or not the estimated error is 0. A second encoder (6) encodes the estimated error when the error is not 0. A third encoder (8) encodes the estimated error whether the value is 0 or not. A mode identifier (2) identifies the mode and an encoding control section (11) selectively operates the first, second, and third encoders (5, 6, and 8) in accordance with the identified mode.
