A document processing device comprises: a document data acquiring part for acquiring document data; a character string extracting part for extracting character strings satisfying a predetermined condition for character string extraction from the document data acquired by the document data acquiring part; a format creating part for deriving the respective features of the character strings extracted by the character string extracting part, and for creating a format containing the derived features in the form of data; a display part on which the character strings extracted by the character string extracting part are displayed in a list form, and on which the format created by the format creating part is displayed; and a format correcting part for correcting the format displayed on the display part. The character string extracting part extracts character strings again to conform to the format corrected by the format correcting part.