A power supply control device including a power supply and a switching control system. The power supply includes a solar power supply unit and an electric network power supply unit. The solar power supply unit includes solar cells and a DC-DC boosting circuit; an output terminal of the solar cells is connected with an input terminal of the DC-DC boosting circuit and the output terminal of the DC-DC boosting circuit supplies power to the exterior. The electric network power supply unit includes an AC-DC rectifying circuit; an input terminal of the AC-DC rectifying circuit is connected to an electric network alternating current input and an output terminal thereof supplies power to the exterior. A ventilating device using the power supply device is also provided.