To generate an outlined image having a high grade while shortening a treating time in consideration of the generation of an outline data having a high image quality and the requirement of an outlining treating time because the outlining treating time is then required owing to the large amount of an information when a high-resolution binary image is outlined although the outline data having the high image quality can be generated in a method outlining a character-object binary image binary-coded at a high resolution as much as possible when characters in a paper original are outlined.

The small character is outlined by the high-resolution binary image, and the large character is outlined by a low-resolution binary image.