User-related data including personal information of a user are stored in a user management computer, which is included in an information management system for a network. An ID and a password exclusively used for opening the user's exclusive page, My Page, provided via the Internet are allocated to the user. In response to the user's input of the ID and the password by telephone or facsimile, the information management system adjusts My Page data based on the user-related data, stores the adjusted My Page data into a My Page server, and opens My Page of the user. This arrangement effectively prevents the personal information of the user from being stored in a server without permission of the user, while simplifying the operations required for opening My Page.