A master content generation unit generates information (master content) that is concretized based on the original idea of a content generator. An intermediate content generation unit re-constructs a complete and concrete content that has an adequate amount of information at a lower level, and generates a content to be sold. When a purchaser (a buyer) issues a request for a desired level, such as for the amount of information, to the intermediate content generation unit via the new content requesting unit, the content is re-constructed in accordance with the request. A content retailing unit provides a price for the master content and the content that is generated by the intermediate content generation unit, and collects the requested purchase price from a buyer. The buyer may select content equivalent to the compensation that corresponds to the buyer's request, and may purchase it from the content retaining unit.