PURPOSE: To separatively extract an area such as a photograph requiring continuous gradation and an area such as a character and a linear image requiring no gradation from a document image.

CONSTITUTION: A document image including characters, a photograph, etc., inputted by multi-gradation is divided into small areas consisting of M horizontal picture elements and N vertical picture elements, the features of respective small areas are extracted, whether each small area is a character area or a photograph area is judged based upon each extracted feature variable, and the attributes of the small areas are stored in a memory. The attribute of each small area is corrected plural times while referring to the attributes of the remarked small area and its near-by small areas and feeding back the attributes. Finally processing appropriate for respective area attributes is executed and outputted.