5. A method of generating a structured document according to claim 2, further comprising the steps of: extracting a keyword from said non-structured document in accordance with a predetermined rule regarding the character strings of a document to be input, and generating a keyword/text model including at least character strings extracted as keywords and other character strings; and converting said keyword/text model into said first structured document by using said parsing rule.
7. A method of generating a structured document according to claim 5, wherein said keyword is extracted by analyzing each character string in said non-structured document with reference to a keyword extraction rule having a correspondence between a format condition of each character string and a keyword name.