PURPOSE: To correctly recognize the size of segmented character by classifying sentences into the mixed sentence of full size and double size characters and the mixed sentence of full size and half size characters, and using prescribed algorithm.

CONSTITUTION: Whether the read sentences are the mixed sentence of the full size and the double size (mode 1) or the mixed sentence of the full size and the half size (mode 2) is discriminated. The character is segmented with the pitch of the double size character as a reference at the time of the mode 1, and with the pitch of the full size character as the reference at the time of the mode 2, whether or not the segmented characters are separated is checked, when they are separated, the size of the characters are recognized with the use of the prescribed comparing expression between the cases of the mode 1 and the mode 2. Thus, the size of the all characters can be correctly recognized.