PURPOSE: To execute processing at a high speed at the time if accessing continuously image data of plural picture elements arranged linearly.

CONSTITUTION: An address of image data to be accessed is set in advance to D flip-flops 17, 18 for setting an address, and the image data of a set address in accessed to an image memory 11. Subsequently, to monadic adder/subtracters 20, 21 for updating an address, how the address is updated at the time of updating the address is set, and an address of a picture element set to the D flip-flops 17, 18 for setting the address is updated automatically to an address of a picture element being adjacent thereto. Thereafter, to the image memory 11, the image data of the address updated as mentioned above is accessed. By repeating the processing, image data of plural picture elements arranged linearly is accessed successively.