PROBLEM TO BE SOLVED : To provide a system which supports determination of real estate investment by presenting the investment adequacy, market rent, cap rate of real estate and the investment interest of real estate bonds (dead and equity) to a real estate broker and a general investor while combining the contrast of statistics by analysis of price decision factors and the accumulation of building scores (investment adequacy) with a competition article.SOLUTION : This system includes a rent calculating means which contrasts and compares rental conditions including the rent of an object building with building attributes and rental conditions of a competition building by using a rent model for a building and estimates rental conditions including the rent corresponding to the building attributes of the object building by a computer and a cap rate calculating means which stocks the building scores (investment adequacy) and demand interest (cap rate) in a building database and compares the building scores of the object building of real estate investment with the building score and demand interest of the competition building to calculate the proper demand interest of the object building by the computer, and totalizes and analyzes the rent, building scores, and demand interest to support real estate investment determination.