PROBLEM TO BE SOLVED : To provide a real estate intermediary management system which enables a user to arbitrarily obtain information even when a real estate object is located in a remote place and to arbitrarily make an investigative visit to the real estate object to be intermediated at any time independently without needing a real estate intermediator to attend him or her, or lock and unlock a door of the object.SOLUTION : A user U accesses a server part 500 of an investigative visit reservation center 11 via a user terminal 12 and acquires information on the real estate object 2 and makes reservation for the visit to the object. A lock means 22 is unlocked by a physical unlocking means 620 given to the user U by identification of the user or a regional communication base 13, and these control and management including re-locking and preparation of the physical unlocking means 620 are performed by a lock management system 610 in a lock management center 600.