PURPOSE: To provide a postal matter processing device which can reliably reproduce a condition in which a software bug generates, and specifies a software which is bugged.

CONSTITUTION: An optical reading part 1 scans postal matter P optically to obtain image information on the postal matter P. An image processing part 2 extracts the address area on the postal matter P based on the obtained image information, and executes the detection of a character line and the retrieval of characters for the address area. A character identification part 3 identifies the retrieved characters. An address identification part 4 identifies address information based on the results of character identification. A postal matter sorting part 5 sorts postal matter P based on the results of address identification. An operation status storing part 6 extracts and stores the operation status of each part 1 to 4. A failure diagnosis part 7 detects the failure of each part 1 to 4 based on information stored in the operation status storage part 6. A failure information storage part 8 stores information corresponding to a failure in the operation status storage part 6, if the failure is detected by the failure diagnosis part 7.