An image coding device that divides each picture of a moving image signal into coding blocks each of which is a unit for predetermined coding, and carries out compression coding on each of the coding blocks by using a motion-compensated prediction, said image coding device comprising: a motion compensation unit for generating a prediction image for each of motion-compensated prediction unit areas into which said each of the coding blocks is divided by using a motion vector selected for said each of the coding blocks or said each of the motion-compensated prediction unit areas; and a variable length coding unit for variable-length-coding compressed data about a compressed difference image between an input signal corresponding to said prediction image and said prediction image, and information about said motion vector to generate a bitstream, and for multiplexing a reference image restriction flag indicating whether or not to restrict a significant reference image area which is an area on a reference image which can be used for said motion-compensated prediction to a predetermined area into the bitstream, wherein each picture is divided into tiles, wherein said motion compensation unit , when said prediction image includes a pixel located outside the significant reference image area while the reference image restriction flag is ON, extends the significant reference image area by adding pixels virtually outside the significant reference image area and generating the prediction image thereby, characterised in that the significant reference image area covers the tile area corresponding to the block and an additional area around the tile area defined by two parameters (dx, dy), and the two parameters (dx, dy) are multiplexed into the bitstream as a part of a higher order header by the variable length coding unit . a motion compensation unit for generating a prediction image for each of motion-compensated prediction unit areas into which said each of the coding blocks is divided by using a motion vector selected for said each of the coding blocks or said each of the motion-compensated prediction unit areas; and a variable length coding unit for variable-length-coding compressed data about a compressed difference image between an input signal corresponding to said prediction image and said prediction image, and information about said motion vector to generate a bitstream, and for multiplexing a reference image restriction flag indicating whether or not to restrict a significant reference image area which is an area on a reference image which can be used for said motion-compensated prediction to a predetermined area into the bitstream, wherein each picture is divided into tiles, wherein said motion compensation unit , when said prediction image includes a pixel located outside the significant reference image area while the reference image restriction flag is ON, extends the significant reference image area by adding pixels virtually outside the significant reference image area and generating the prediction image thereby, characterised in that the significant reference image area covers the tile area corresponding to the block and an additional area around the tile area defined by two parameters (dx, dy), and the two parameters (dx, dy) are multiplexed into the bitstream as a part of a higher order header by the variable length coding unit . <EOS>