To efficiently perform picture readout, matching processing, and visual inspection.

An individual number printed on a medium is optically read in step S1, and a first matching between read character picture data of the read individual number and standard character picture data is performed in step S2. If a matching error is judged in step S2, the read character picture is shaped by expansion or contraction in steps S3 and S5, and a second matching between this shaped picture data and standard character picture data is performed in steps S4 and S6. If matching is successful in steps S2 and S4 or S6, read character picture data is subjected to character recognition and is converted to a recognized individual number, and a third matching between this number and a predicted individual number of performed in step S7. If a matching error is found in step S6 or S7, read character picture data or the like is stored in step S8, and it is displayed on a monitor in step S9. An operator watches the monitor to input the visual discrimination result in step S1-, and this result is stored in step S11, and it is printed out by a printer in step S12.