PROBLEM TO BE SOLVED : To provide a real-estate rent guarantee management system that enables a person who desires to rent a house to make a rent contract with a real estate agent even if a credit check by a credit company indicates no creditworthiness, and facilitates management. SOLUTION : When the credit company 13 serves as a guarantor needed for a real estate rent contract of a tenant 11, a guarantee company 14 different from the credit company 13 guarantees for the tenant to the credit company 13. At this time, a common guarantee code is set in a credit management ledger of the credit company 13 and a guarantee management ledger of the guarantee company 13 to establish a link. Those are efficiently processed by a credit managing device 22 and a tenant guarantee managing device 23. COPYRIGHT : (C)2005, JPO&NCIPI