To provide an advertisement system which can make a user surely read an advertisement via the Internet and also to provide a questionnaire research system, which makes the user answer the questionnaire via the Internet without fail and without psychological load on the user.

A server is connected to the Internet and records the contents that can be used by a user, and a contents using button and an advertisement are provided, in relation to each other on the entry screen of the contents. The advertisement is provided with its related questions, and the server will allow the user to use the contents, under the condition of only when the answers for these questions are received from the user.