To provide a virtual property data formation system capable of providing minimum necessary information for purchasing a real-estate property in the auction of this property, while making the position or the like of the property not identifiable.

Evaluation points of price and geographic conditions of a property of assessment are computed based on data for the position, area, and geographic conditions of the property of assessment, and virtual property data having the same area, price and total of evaluation points as the property of assessment with each item of the evaluation points being changed are formed.