PURPOSE: To acknowledge a document prepared as an electronic document in a terminal without temporarily printing out it by synthesizing an acknowledged image with a document displayed on a display means when inputted personal identification information is decided as a valid information and the acknowledgement of the document is instructed by an instructing means.

CONSTITUTION: A document body data file 2 stores the document data of plural documents, a recognition image file 3 stores an image such as a seal to be impressed on a document to be acknowledged or a sign and a password file 4 stores a password, a personal name and the name of the file 3 for storing the image of the person's seal impression or sign. When personal identification information inputted by an input means 5 is decided as a valid one by a checking means 200 and the acknowledgement of the document is instructed by the instructing means 5, a document data handling device 100 synthesizes the acknowledgement image stored in the means 3 with the document displayed on a display means 5. Consequently, the prepared document can be acknowledged in the electronized state without printing it.