An operator can select image processing for a half tone image area among a plurality of processing methods, and image processing appropriate for the image can be carried out thereby. An original image is read by an image sensor 1 and output through either simple binary conversion by binary conversion means 3 for character processing or half tone image processing by binary conversion means 2 for photograph processing. Judging means 6 judges whether image data are of a character image area or a half tone image area, and switches output between the binary conversion means 3 for character processing and the binary conversion means 2 for photograph processing. The binary conversion means 2 for photograph processing includes error diffusion processing means 10 and dither processing means 11. By setting of setting means 13 carried out by an operator, output from either the error diffusion processing means 10 or the dither processing means 11 is selected for a half tone image.