A moving image coding apparatus which divides a moving image into macroblocks and codes each of the macroblocks, the apparatus comprising: a macroblock size determination means for determining a size of each of the macroblocks on a sequence by sequence basis or on a frame by frame basis, the sequence is a set of a plurality of continuous frames and each of the continuous frames is temporally divided from the moving image; a macroblock dividing means for dividing the moving image into the macroblocks each having the size determined by the macroblock size determination means; a macroblock coding means for determining a coding mode for each of the macroblocks, and for coding pixel values in each of the macroblocks according to the determined coding mode, wherein the macroblocks are further divided into regions on each of which motion compensation is to be performed, the size of said regions being determined according to the macroblock size; a block dividing means for dividing the macroblock into a block on which an orthogonal transformation and quantization process is performed; a transformation and quantization means for performing the orthogonal transformation and quantization process based on the block; and a multiplexing means for multiplexing information indicating whether to change the macroblock size information for each frame or each sequence into a bitstream in units of each sequence, and for multiplexing, when changing of the macroblock size information for each frame is selected, the macroblock size information determined by the macroblock size determination means into the bitstream in units of each frame, and for multiplexing, when changing of the macroblock size information for each sequence is selected, the macroblock size information into the bit stream in units of each sequence and for multiplexing block size indication information indicating the size of the block into the bitstream. a macroblock size determination means for determining a size of each of the macroblocks on a sequence by sequence basis or on a frame by frame basis, the sequence is a set of a plurality of continuous frames and each of the continuous frames is temporally divided from the moving image; a macroblock dividing means for dividing the moving image into the macroblocks each having the size determined by the macroblock size determination means; a macroblock coding means for determining a coding mode for each of the macroblocks, and for coding pixel values in each of the macroblocks according to the determined coding mode, wherein the macroblocks are further divided into regions on each of which motion compensation is to be performed, the size of said regions being determined according to the macroblock size; a block dividing means for dividing the macroblock into a block on which an orthogonal transformation and quantization process is performed; a transformation and quantization means for performing the orthogonal transformation and quantization process based on the block; and a multiplexing means for multiplexing information indicating whether to change the macroblock size information for each frame or each sequence into a bitstream in units of each sequence, and for multiplexing, when changing of the macroblock size information for each frame is selected, the macroblock size information determined by the macroblock size determination means into the bitstream in units of each frame, and for multiplexing, when changing of the macroblock size information for each sequence is selected, the macroblock size information into the bit stream in units of each sequence and for multiplexing block size indication information indicating the size of the block into the bitstream.