An image decoding device is provided that decodes, without an increase in the circuit size, a coded video sequence including a large-size block. The image decoding apparatus includes: a block division unit which divides a current block that is to be decoded and is included in a picture of the coded video sequence, into sub-blocks; an image obtainment unit which obtains, for each of the sub-blocks, image data corresponding to the sub-block from a recording medium; a prediction unit which generates, for each of the sub-blocks, a predicted image of the sub-block, based on the image data obtained by the image obtainment unit; and a reconstruction unit which reconstructs each of the sub-blocks, by adding the predicted image generated for the sub-block to the sub-block.