A solar power generation system includes a string, an inverter, a first shutoff device, and a second shutoff device. The string includes a plurality of solar cell module groups. The first shutoff device cuts off connections between the plurality of solar cell module groups connected to a first electric path in response to a first control signal. The second shutoff device is driven by power supplied from the first shutoff device and cuts off connections between the plurality of solar cell module groups connected to a second electric path in response to a second control signal. The first shutoff device includes a first switching unit which includes a first open and close unit and a first semiconductor switching device connected in parallel with the first open and close unit. The first semiconductor switching device is turned ON before the first open and close unit is operated.