To speedily spread a photovoltaic power generation system by canceling the lack of install places and funds.

In a photovoltaic power generation system 10, an enterpriser server 14 collects a roof provider and an investor through the Internet 12. Then, information on the roof to be provided is inputted from a roof provider PC 16 and on the basis of that information, the enterpriser server 14 predicts an annular power generation quantity or CO2 reduction quantity and collects the investor while publishing these predictive values. When the provision of funds is applied from an investor PC 18 and the required funds are reached, an enterpriser really installs and operates a solar battery panel on that provided roof. Then, a dividend is paid to the investor corresponding to the power generation quantity.