PURPOSE: To facilitate the setting of a threshold and to decrease the generation of an erroneous recognition by executing the matching by designating a part of the majority of picture elements to a picture element being outside of the object so that a constitution ratio of a pattern constitution picture element and other picture element becomes the same degree.

CONSTITUTION: Binary image data of an input image is given to a matching processing circuit 20, and also, a set value of each sample pattern register in a matching circuit 21 of each line is shifted by a sampling clock, by which a standard pattern is scanned relatively against the input image, and in each matching circuit 21, a coincidence frequency of the input image and the standard pattern is counted by a counting circuit 24, counted up by an adder group 22 and a coincidence degree is calculated. This calculated value is compared with a threshold value, and it is decided that a pattern which coincides with the standard pattern exists in a position in which the calculated value becomes maximum after the scanning is completed.