1. A information extraction rule making support system comprising: a storage section storing an extraction object document, which is an electronic document of an information extraction object; an input section inputting a plurality of extraction rules, which are rules used to extract information from said extraction object document; an information extraction section respectively deriving extraction results matching each of said extraction rules from said extraction object document stored by said storage section, using each of said extraction rules inputted by said input section; and a rule relation creating section creating a rule relation network indicating a relation between each of said extraction rules by analyzing an overlapping relation and including relation between extraction results derived by said information extraction and linking said extraction rules that the extraction results overlap or include, based on the result of the analysis; wherein said rule relation creating section derives an overlapping ratio indicating an overlapping relation between each of extraction results derived by said information extraction section, by analyzing an overlapping relation between said extraction results, and links corresponding extraction rules based on said overlapping ratio derived.