Abstract: An advertisement distribution system is provided, by which advertisements with contents that a user demands can be distributed while assuring security concerning user information. According to the advertisement distribution system, in a network environment including an Internet connection device that establishes relay and connection between a LAN environment and an Internet environment, the Internet connection device allows to receive and store information concerning a user of a user device connected over the LAN environment; to compare received attribute information of advertisement contents data with the stored user information so as to sort out the advertisement contents data; to receive and store the advertisement contents data that are to be distributed from a distribution device used by an advertisement contents distributor; and to distribute the advertisement contents data in response to a request.