Abstract: A monitor device is equipped with an external communication section and an information extraction section, which receive position information from a reader/writer that calculates position information of a RFID tag that was disposed on each of plural articles or users, and a specifying section which specifies a combination of a user and an article which enter/leave in/from a safekeeping room concurrently, on the basis of the received position information, and therefore, it is possible to specify a combination of a user and an article which enter/leave in/from the safekeeping room with high precision.