A moving image decoding apparatus includes a region boundary position information extracting unit which extracts region boundary position information between a clean region including at least one block encoded such that a pixel value is guaranteed to be decoded correctly, and a non-clean region, a region classification unit which specifies the clean region and the non-clean region in each picture based on the region boundary position information, a referenceability determining unit which, when a decoding target block belongs to the clean region, determines that blocks in the clean region in the decoding target picture and blocks in the clean region in the reference picture are referenceable, and, when the decoding target block belongs to the non-clean region, determines that all of blocks of the decoding target picture and the reference picture are referenceable, and a decoding unit which decodes the decoding target block with reference to only the referenceable blocks.