PURPOSE: To optionally process electric signals for visually indicating appearances of text sections on articles of respective groups by a same method and directly comparing the signals so as to visually display the appearances of the text sections by the compared electric signals.

CONSTITUTION: A set of articles formed of a group of two or more articles 4, 5 is moved, text sections of respective articles are scanned by optical scanning devices 6, 7, electric signals indicative of scanned text sections are generated, and signals indicative of text sections of articles of respective groups are compared by a comparing devices 8. Therefore, whether the text section are approximately identical or not is confirmed. If the text sections are approximately identical, the articles are combined. If they are not identical, the combination of the articles is stopped.