To provide a solar energy power generation system where starting timing corresponding to an installation system can be determined without being affected by a characteristic change of a solar cell due to secular degradation and a change of installation environment so that generated power of the solar cell can effectively be used.

The system is provided with a data storage part 44 storing an output voltage value of the solar cell 1 at previous starting time of a power conditioner 2 as a reference voltage value, a voltage detection part 41 detecting the output voltage value at starting time of the solar cell 1 at this time and a starting judging part 42 comparing the output voltage value of the solar cell 1 with the reference voltage value. In the solar energy power generation system, the power conditioner 2 is started with a comparison operation when the output voltage value of the solar battery 1 exceeds the reference voltage value and the output voltage value is not more than a prescribed voltage value.