A content billing method for performing billing processing corresponding to use of digital content. After the operation is started, search management processing is performed. In the search management processing, information on whether or not a search period expires is managed. When the search period expires, content is searched for in automatic-search-and-collection processing, and identification information of the content is extracted and use information is generated in identification-information recognition processing. The use information is recorded and managed in use-information management processing. Subsequently, in state-of-use recognition processing, a status of use in a predetermined period is recognized based on the use information, and state-of-use information is generated. Finally, in use-fee calculation processing, a use fee corresponding to the state-of-use information is calculated.