To provide a document editing device which can simplify its input operation, can perform an input job in a short time and also can reduce the program size.

A display device 2 has a learning pattern display part, gives the character strings inputted from an input device 1 to a learning mechanism 6 for support of a document editing job and displays a pattern, i.e., the output of the mechanism 6 at the learning pattern display part. Thus, the editing efficiency and the readability of an editing object document can be improved by means of a display pattern. The mechanism 6 includes a learning segment production part 10 which segments the inputted character string data and produces a learning segment that is available for learning a pattern and a pattern learning part 11 which inputs the produced learning segment and learns the pattern based on the learning algorithm of a pattern language. Then the input is limited to the part 11 by means of the syntactic characteristic of the sentence to be edited.