1. An item recommendation system comprising: a feedback receiving unit receiving feedbacks with respect to items by users; a feedback history storage unit storing information of feedbacks received at present or in the past by the feedback receiving unit in units of combinations of users and items; a relevance calculation unit calculating relevance between items base on first information indicating the degree in which the same user gives feedbacks to respective items and second information indicating the degree in which many users give feedbacks by using feedback information stored by the feedback history storage unit when receiving the feedback by the feedback receiving unit; and a recommendation unit immediately recommending items having higher relevance with respect to the item to the user who has given the feedback to the item by the feedback receiving unit based on the relevance calculated by the relevance calculation unit.