Image encoding apparatus, image decoding apparatus, image encoding method and image decoding method

Picture coding device that divides each picture of a moving picture signal into coding blocks, each of which is a unit for predetermined coding, and performs compression coding on each of the coding blocks using a prediction with motion compensation, said image coding device comprising: a motion compensation unit (9) for generating a prediction image for each of the areas of the motion-compensated prediction unit into which said each of the coding blocks is divided using a motion vector selected to each of the coding blocks or said each of the areas of the motion-compensated prediction unit; and a variable length encoding unit (23) for variable length encoding compressed data on a compressed difference image between an input signal corresponding to said prediction image and said prediction image, and information about said motion vector for generating a bit stream and for multiplexing a reference image restriction indicator (105) indicating whether or not a significant reference image area that is an area in a reference image should be restricted. reference that can be used for said prediction with motion compensation to a predetermined area in the bit stream, in which each image is divided into tiles, in which said motion compensation unit (9), When said prediction image includes a pixel located outside of the significant reference image area while the reference image restriction indicator (105) is ON, it extends the significant reference image area by adding pixels virtually outside of the image area of meaningful reference and thus generating the prediction image, characterized in that the significant reference image area covers the mosaic area corresponding to the block and an additional area around the mosaic area defined by two parameters (dx, dy), and the two parameters (dx, dy) are multiplexed in the stream bits as part of a higher-order header by the variable-length encoding unit (23).