PURPOSE: To reduce miscorrection at the time of correcting a read result by adding hierarchical information to a knowledge processing result based upon a knowledge processor.

CONSTITUTION: A hierarchical information adder 22 adds hierarchical information to each candidate character of the recognized result of each field in the knowledge processing result of the knowledge processor 10. The recognized result is sent and displayed to/on a display device 1. Since the candidate character having no hierarchical relation is not displayed at the time of using the hierarchical information, miscorrection at the time of correcting the read result can be reduced.