1. An information processing apparatus comprising: label acquisition means for acquiring a label assigned by a user to a content selected among a plurality of contents; user certainty factor setting means for setting a user certainty factor that refers to a certainty of the label assigned by the user; wherein the user certainty factor setting means sets the user certainty factor on the bases of at least one of a necessary amount of time the user spends and the number of label changes made by the user until the user decides upon the label to be assigned to the content; label prediction learning means for performing label prediction learning to predict the label on the basis of characteristics values of the content to which the label is assigned and the label; label prediction means for predicting a label regarding a content to which the label is not assigned on the basis of the results of the label prediction learning and the characteristics values of the content, and for calculating a label certainty factor that refers to a certainty of the predicted label; user certainty factor prediction means for performing user certainty factor prediction learning to predict the user certainty factor on the basis of the characteristics values of the content to which the label is assigned and the user certainty factor, and for predicting a user certainty factor of the predicted label regarding the content to which the label is not assigned on the basis of the results of the user certainty factor prediction learning and the characteristics values of the content; and selection means for selecting a content to be next assigned a label among contents to which labels are not assigned.