PROBLEM TO BE SOLVED : To improve efficiency of management cost of rental property by effectively using a crime prevention device for security securing in time of a self-visit.SOLUTION : Locking is released only in a time zone previously notified to a visit applicant by use of an electric lock 11 provided in the rental property 1 to make the applicant perform the self-visit, and behavior of the visitor is monitored by a machine guard device 12. After move-in, a guard state signal K from the machine guard device 12 is changed over such that the signal K is sent to a guard center 4 by remote control by a management server 21, by a request of a resident. Thereby, installation equipment installed in the rental property 1 can be effectively used to enable extremely efficient real estate management.COPYRIGHT : (C)2008, JPO&INPIT