PURPOSE: To attain high speed processing by processing prediction error data obtained by applying adaptive prediction to picture data as a block and applying run length coding to a run length of a zero block and a bit state of a non-zero block succeeding thereto.

CONSTITUTION: A compression mode is fetched from a picture bus 2 to a picture data input output section 8, the picture data are sent to a line memory control section 9, the picture data of one preceding line are read and fed to an adaptive prediction/inverse prediction section 11, in which the data are converted into prediction error data and given to a code processing section 14 and outputted while being subject to run length coding therein. A 16-bit alignment section 12 an 8-bit PBK ling boundary code to a head of lines of one page comprising variable length codes and gives a NOR line boundary code to the other parts, and when codes from the code processing section 14 reach 16-bits, the code is fed to a ping-pong buffer control section 10 and written in ping-pong buffers 4, 5. Code data are fed to a 32-bit alignment section 13, in which the data are again shaped and the result is fed to a system bus 1.