To increase the incentive to use cooperative advertising while securing fairness for advertisers, and reduce a user's burden of information selecting.

A cooperative advertising system includes: means for storing content data for a web page having a window for displaying individual advertisements; means for storing extraction conditions for extracting individual advertisement data of a predetermined number of advertisers from a plurality of advertisers; display processing execution means for transmitting content data and a program for displaying advertisements to a user terminal when there is an access to the web page; and advertising information extraction means that, by the execution of the program for displaying advertisements on the user terminal, receives an advertisement display request sent together with history data in which access status is recorded, extracts a predetermined number of individual advertisement data based on the history data and the extraction conditions, and sends them to the user terminal, thereby outputting and displaying the individual advertisements in the window for displaying advertisements on the web page displayed on the user terminal.