PURPOSE: To improve the efficiency of polishing/correcting work of a document by analyzing correction information obtained by comparing an original document with a corrected document and obtaining detailed correction information corresponding to a calibration code.

CONSTITUTION: An original document is inputted to an original document file 1, and after correcting the document, the corrected document is inputted to an updated document file 2. A control part 4 controls a file input part 3, reads out documents from the input part 3 and a correct information acquisition managing part 6 compares the read document with correct data and stores corrected information in a corrected information file 5. A detailed corrected information acquisition managing part 8 analyzes these corrected information, stores the detailed corrected information in a detailed corrected information file 7 and sends the information also to a sequential display part 9. The display part 9 displays a corrected position using a calbration code based upon the detailed corrected information. Even at the time when a part in a moving part is further updated, the corrected position can be accurately recognized as a corrected part and also the contents of calbration can be judged at a glance.