To provide a system which improves various problems, although housing which circulate among sellers of engineering firms, construction firms and real estate companies and buyers of personal customers now have problems in the point of environment, durability, and economical efficiency at the circulation sale of the housings.

A consultant in this system intervenes two persons who are the seller on the supply side and the buyer on the demand side by Internet; establishes a firm triangle structure where flow of advertisement, flow of order, flow of service, and flow of money produced among three persons are accompanied; and enhances the added value of circulating housings by using know-how concerning housing environment improvement technology, mainly composed of planting, that themselves or others have.