To obtain stable advertisement effect while complying with a change in interest of a user viewing advertisement contents.

A history information summarization part 63 in a history information summarization device 60 summarizes the number of reception of output requests, which are given by an arbitrary user for a predetermined web page, within a predetermined period, that is, the number of clicks made on a banner advertisement by the arbitrary user is summarized. When a fixed distribution ratio calculation part 83, a variable distribution ratio calculation part 84, and a distribution ratio calculation part 85 in an advertisement distribution ratio calculation device 80, calculate a distribution ratio for each of the banner advertisements based on the summarized click frequency information, a distribution ratio based on a general response tendency to the advertisement contents by various users is calculated.

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