A pattern recognizing method for matching a binary or ternary reference image and an input grayscale image, having a precision similar to the method in which a plurality of binary reference images are generated by supposing settable various binarization threshold value and comparing the distances between the plurality of binary reference images and the grayscale image, and enabling the processing time to be shorter. The first accumulated histogram of the pixels of the grayscale image corresponding to a high density region of the binary reference image and the second accumulated histogram opposite to it and of the pixels of the grayscale image corresponding to the low density region of the reference image are generated and summated. The existence or absence of a pattern is judged by comparing the minimum value of the summated accumulated histogram and a threshold value.