an object of the present invention is to data compress a binary image which includes a pseudo expressed halftone image effectively . to attain this object , an image processing apparatus of the present invention comprises region division means for dividing an input binary image data into a region of a pseudo expressed halftone image portion and a region of another portion , first encoding means for generating multi - value image data from binary image data of said pseudo expressed halftone image portion and encoding the obtained multi - value image data , second encoding means for encoding at least a part of the binary image data from a portion other than the pseudo expressed halftone image portion .