PROBLEM TO BE SOLVED : To solve the problem that the price of construction becomes comparatively high as a result since the price of construction is conventionally determined under the leadership of a selling company when a client (consumer) is to perform the construction of painting, construction for bathtub, construction for retiling the roof, construction for guard, construction for extension or reform or construction for interior repapering.SOLUTION : A home page is opened for establishing a direct mediation system for reform on the Internet and integrated on a WEB site for explaining a specification by article courses and automatically calculating the unit cost for each of constructions. Information is provided on the Internet so that the client can prepare a simplified estimate out of article contents retrieved by a personal computer. Further, the guarantee of undertaking charges and securing of the dealer can be promised by exchanging the general contract document with a constructor so as to enable contracting at ease. Therefore, a mediation system, with which a proper estimate can be mediated until reaching matching between the client and the contractor dealer when a construction request is received from the client, can be provided.