To provide a housing design competition supporting system capable of ensuring a sense of fairness in inter-designer competition by making the specifications of designing tools to be used by plural designers common to this system, and allowing the designers to always use the latest and strongest designing tools, and for allowing a client to compare or correct all the plural design plans in the same environment.

In this system for supporting housing design competition through the Internet, a server being the main body of system management is provided with layout design software which can be commonly used by the terminal of a client and the terminals of plural designers, software for interior simulation, and software for housing appearance design. The server is provided with a data base in which the result of the designed layout or interior simulation or the result of the housing appearance design is preserved, and the design information preserved in this data base is made readable from the terminals of the plural providers.