According to a data analysis method by which time required for data analysis is shortened and practicality is improved, a client terminal requests institution terminals to perform analysis of a matching attribute; each of the institution terminals encrypts an element belonging to the matching attribute within a database and sends the converted data to an outsource terminal; the outsource terminal integrates the plurality of converted data sent from the institution terminals and sends the integrated converted data to the institution terminals; and each of the institution terminals compares each matching attribute of a plurality of the elements within the database of the institution terminal against the integrated converted data, thereby identifying, as a common element, an element associated with the matching attribute and held in common by the institution terminals.