1. A printing management system for inserting watermark information into a file and printing the file, comprising: means which specifies a file to be printed from file storage means for storing a file; keyword storage means which stores a keyword which is a keyword that, if included in the file to be printed, signifies that watermark information is to be inserted into the file to be printed; watermark information storage means which stores the keyword and the watermark information in association; keyword search means which searches for the keyword included in the file to be printed by referring to the keyword storage means; watermark information acquisition means which acquires watermark information corresponding to the found keyword by comparing the found keyword with the keyword stored in the watermark information storage means; watermark insertion means which inserts the acquired watermark information into the file to be printed; printing means which prints the file to be printed into which the watermark information is inserted; hash calculation means; and file information registration means, wherein the watermark information storage means includes a keyword definition file that stores a watermark policy, which indicates the level of importance of the keyword, and the keyword in association, and a watermark definition file that stores the watermark policy and the watermark information in association, the watermark information acquisition means acquires the watermark policy corresponding to the found keyword, and acquires the watermark information corresponding to the acquired watermark policy, the hash calculation means calculates a hash of the file to be printed, and the file information registration means acquires from the keyword definition file the watermark policy corresponding to the found keyword, and registers in a hash policy file the acquired watermark policy and the calculated hash in association.