1. A color image encoding method which inputs and encodes color image data, comprising the steps of: dividing the input color image data into a plurality of blocks; maintaining the image data of the blocks; and run-length modeling the block models using surrounding reference pixels when the specified value is exceeded when the image state in a block which was pre-scanned is temporarily run-length encoded, and the ratios where the value of the run becomes 1 and 2 are a specified value or less.