1. An information processing apparatus comprising: a first similarity degree calculating section which calculates a degree of similarity between a predetermined item and a first calculation target item; a related item determining section which determines a predetermined quantity of calculation target items as one or more related items of the predetermined item, the calculation target items being in a descending order of degree of similarity; and a relation degree adding section which, when the first calculation target item is one of the one or more related items related to the predetermined item, adds a degree of relation of the first calculation target item to the degree of similarity of the calculation target item calculated by the first similarity degree calculating section, wherein meta information related to the first calculation target item is added to the predetermined item based on a behavior history of a user, the meta information being added to calculate the degree of similarity between the predetermined item and the first calculation target item.