An 8-bit input image data value has its range adjusted by an image range conversion lookup table and is converted into a 4-bit dither image data value f2 with a multi-value dither circuit. The converted 4-bit dither image data value f2 is error-corrected by an error correction unit, and then binarized with a predetermined binarization threshold value of Th=8. An error between binarized data value g and error-correction image data value f2' is calculated by the error calculation unit to be stored in an error storage line memory. Error data e' is provided with respect to a pixel of interest by a peripheral error weighting filter, whereby error is propagated to peripheral pixels of the pixel of interest. As a result, an image processing apparatus of high picture quality, high speed, and low cost is provided.