PROBLEM TO BE SOLVED : To float real estate investment money by guaranteeing conversion into money by means of repurchase.SOLUTION : A server 1A provides a want ad through Internet communication. When a selling and buying contract is made between an investor 3, who applies for the ad through Internet communication to the server 1A, a management trust contract is assured for distributing a dividend in the remaining amount deducting various costs from a rent, which is provided by renting target real estate 5, to each of investors 3 according to a prescribed order. The server 1A provides disclosed information such as dividend rate H, vacancy rate κconcerning the target real estate 5 and the business state of the enterprise 1 or the like dealing with the target real estate 5 through Internet communication to be investor 3. When a vacant room exists in renting of the target real estate 5, and the investor 3 it to carry out a repurchase right based on the selling and buying contract according to the disclosed information, the enterprise 1 or the like repurchases the share of the investor 3 with a predetermined rate.