To extract the feature of a thin line without increasing noise components even when the line width of a character line constituting a character is different at the time of extracting the feature matrix of the character.

The line width W of a character pattern 20 is obtained by line width detecting processing of a line width detecting part 5 and a sub-pattern consisting of the directional components of the character is obtained by sub- pattern extracting processing of a sub-pattern extracting part 7 to be stored respectively in plural memories 8 to 11. A feature matrix preparing part 12 executes sub-pattern scanning processing with respect to each sub-pattern, calculates a distance between a white-to-black varying point and a black-to- white varying point on each scanning line, obtains the middle point of the varying points only when the distance is equal to or longer than a distance threshold value T, and counts up a middle point cumulative memory 13 corresponding to cell areas obtained by dividing the sub-pattern to prepare a feature matrix f by this count up result.