1. An image document processing device for giving a document name to each of accumulated image documents and managing the image documents, said image document processing device comprising: a font-feature dictionary for storing features of images of individual characters; a headline clipping section for clipping a headline region included in an input image document; an image-feature extracting section for dividing an image of a character sequence included in the headline region into images of individual characters and extracting features of the images of individual characters; a candidate-character-sequence generating section for selecting, as candidate characters, images of characters each having high degree of matching of features based on the features of the images of individual characters that have been extracted by the image-feature extracting section and with reference to the font-feature dictionary, so as to generate a candidate character sequence corresponding to the character sequence, the candidate-character-sequence generating section adjusting the candidate characters included in the candidate character sequence through a semantic analysis method so as to generate a meaningful candidate character sequence; and a document-name generating section for generating a first document name for the input image document, the first document name including the meaningful candidate character sequence generated by the candidate-character-sequence generating section.