Disclosed is a system for detecting falsification, the system having: a confirmation information preparing unit preparing confirmation information of source data of published content published on the Internet; a confirmation information holding unit holding the confirmation information of the source data at a predetermined point in time; a source data alteration detecting unit detecting an alteration in the source data; a reflecting unit reflecting the altered source data in the confirmation information of the confirmation information holding unit and in the published content; a published content alteration detecting unit performing alteration detection on the published content; a published content alteration notifying unit notifying a predetermined terminal of information relating to altered published content; and a controlling unit controlling detection of inappropriately altered published content, based on the confirmation information of the source data and on the confirmation information of the published content.