PROBLEM TO BE SOLVED : To convert bad assets owned by administrative organs into good assets, without requiring any extra burden, and to provide a chance of transferring the chance of the transaction of the carbon dioxide emission right, the market of which is not established yet in Japan, to medium and small sized enterprises. SOLUTION : By exchanging the equivalent leasehold, while keeping the real estate ownership of the original owner, an administrative organ owning an idle land also keeps the emission right of carbon dioxide being absorbed by the forest of foreign country for exchanging the leasehold and can transfer that emission right.