The invention acquires article data (S1), extracts characteristic words from the acquired article data (S2), specifies a characteristic word which is not stored as a local area word in a database 12b which stores a local area word indicating a local area in association with geography information for specifying the local area, from the extracted characteristic words (S3), acquires a result of searching performed in a search device, according to the specified characteristic word (S4 and S5), specifies a local area related to article data based on the search result and finds geography information (S6), and stores the specified characteristic word in the database 12b as the local area word in association with the specified local area (S7).