To provide a photovoltaic power generation device capable of efficiently selecting a secondary battery so as to maximize a generating capability of a solar battery and performing a charging/discharging operation so as to equalize a charging depth of the secondary battery.

A solar battery operating voltage decision unit 18 determines whether an operating voltage of a solar battery 11 by a maximum power point tracking control is in a middle range of voltages of the rated voltages of two secondary batteries 12 or not when a charging/discharging control for the secondary battery 12 is required during the maximum power point tracking control. A first secondary battery selection unit 19 selects the one secondary battery of which the rated voltage is closer to the operating voltage of the solar battery 11 when the operating voltage is determined to be out of the middle range of voltages. A second secondary battery selection unit 20 selects the one secondary battery 12 of which an output power is higher when the solar battery is operated by the maximum power point tracking control unit 23, when the operating voltage is determined to be in the middle range of voltages. A secondary battery connection unit 22 connects the selected secondary battery 12 with the solar battery 11 of a direct current system 14 in parallel by a switching circuit 13.