To provide a system with which a building constructor shows wide range of customer model plans of a house and a customer can accurately and quickly communicates his images of a house to the building constructor.

Building constructor distributes widely a storage medium 3 that stores by updating a construction advertising and an application program of contract for construction work as needed that contains the model plans of a house capable of displaying an image at least, and floor plans of soft ware of CAD for generating customer's desirable disposition of a room with making correction and modification on the model floor plans, and calculating program for expenses that calculates construction costs and accouterment charges based on information of selected appearance of the house. The customer gains access to model plans by practicing the application program with a computer 4 of a customers side. As well as abstracting or identifying the appearance and the structure of a house, which customer images, from model plans, the customer generates the floor plans for the desirable disposition of the room, and sends it as construction specifications and orders. The building constructor adjusts it with a customer based on a specification for order, and undertakes a construction according to the decided construction specification.