An image processing method for decoding input encoded image data, which has undergone encoding processing by a predetermined format, image processing the decoded image data, and encoding the image-processed data to create output encoded data includes repeating the process of decoding, image processing and encoding processing and outputting the image data in image processing units subject to the image processing; and sorting the encoded data obtained from the repeated processing step and creating the output encoded data in an order defined by the format of the output encoded data for performing encoding processing on one picture plane. In this case, the repeated processing step includes decoding the input encoded data in the image processing units and outputting image data, image processing the decoded image data in the image processing units, and encoding processing the image-processed data in encoding processing units.