IMAGE DECODING APPARATUS

A lateral directional difference calculating unit 21 calculates a change degree between pixel levels of pixels adjacent to each other through a boundary of a decoded block and a block adjacent to the decoded block in a lateral direction and calculates a change degree between pixel levels of pixels placed in the block adjacent to the decoded block in the lateral direction, a lateral directional continuity judging unit 23 judges the continuity between the decoded block and the block adjacent to the decoded block in the lateral direction. A longitudinal directional difference calculating unit 22 and a longitudinal directional continuity judging unit 24 are operated in the same manner, a block continuity judging unit 25 judges the continuity between the decoded block and each block adjacent to the decoded block, and an error macro-block judging unit 26 detects an error macro-block according to a judging result of the block continuity judging unit 25.