PROBLEM TO BE SOLVED : To show a rental user that an offering still stands, the rent, the floor plan, conditions, or the like without having the user directly telephone or visit.SOLUTION : A database of descriptions of rentals and commodity introduction information is provided in a form allowing display on the Internet, and a URL address with respect to a rental and commodity introduction information in the same database is introduced in interlock with the rental by a URL address mark printed on a floor mat of a building. A function is provided for registering an E-mail address if the rental is not vacant, and information of the rental is notified to the registered E-mail address when a manager registers a vacant rental.COPYRIGHT : (C)2006, JPO&NCIPI