An image decoding apparatus comprising: a bit stream analysis unit to which a bit stream comprising header information and coded image data is input; and an image restoration unit that executes decode processing on the coded image data which is supplied from the bit stream analysis unit and executes filter processing on decoded data resulting from the decode processing, wherein the coded image data is image data obtained by dividing one frame of an original image into a plurality of tiles which are rectangular regions and coding each of the tiles, each of the tiles comprising one or more coding blocks which are units of coding, arranged in a matrix, wherein the bit stream includes the coded image data coded for each tile in order from a tile on the left end, top row within the one frame, going through a right adjacent tile in turn, followed by tiles on one row down from left to right sequentially, and up to the bottom row in the frame, and coded for each coding block in each tile in order from a coding block on the left end, top row within the tile, going through a right adjacent coding block in turn, followed by coding blocks on one row down from left to right sequentially, and up to the bottom row in the tile, wherein the header information includes size information of the each tile, and wherein the image restoration unit serially executes decoding coding blocks in order from a coding block on the left end, top row within the one frame, going through a right adjacent coding block in turn, followed by coding blocks on one row down from left to right sequentially, and up to the bottom row in the frame, independently of whether or not there is a tile boundary within the one frame, and filtering decoded image data around a boundary, between horizontally adjoining tiles characterised in that the image restoration unit executes decoding and filtering successively for a row, and across a tile boundary decoded results of a left-hand tile are directly passed to the filter processing for a right-hand tile. a bit stream analysis unit to which a bit stream comprising header information and coded image data is input; and an image restoration unit that executes decode processing on the coded image data which is supplied from the bit stream analysis unit and executes filter processing on decoded data resulting from the decode processing, wherein the coded image data is image data obtained by dividing one frame of an original image into a plurality of tiles which are rectangular regions and coding each of the tiles, each of the tiles comprising one or more coding blocks which are units of coding, arranged in a matrix, wherein the bit stream includes the coded image data coded for each tile in order from a tile on the left end, top row within the one frame, going through a right adjacent tile in turn, followed by tiles on one row down from left to right sequentially, and up to the bottom row in the frame, and coded for each coding block in each tile in order from a coding block on the left end, top row within the tile, going through a right adjacent coding block in turn, followed by coding blocks on one row down from left to right sequentially, and up to the bottom row in the tile, wherein the header information includes size information of the each tile, and wherein the image restoration unit serially executes decoding coding blocks in order from a coding block on the left end, top row within the one frame, going through a right adjacent coding block in turn, followed by coding blocks on one row down from left to right sequentially, and up to the bottom row in the frame, independently of whether or not there is a tile boundary within the one frame, and filtering decoded image data around a boundary, between horizontally adjoining tiles characterised in that the image restoration unit executes decoding and filtering successively for a row, and across a tile boundary decoded results of a left-hand tile are directly passed to the filter processing for a right-hand tile.