A power-supply unit has an electric connection box operable to supply an electric power of a battery to loads and a power supply operable to control first voltage supplied from the battery and outputted through the electric connection box and supply second voltage into which the first voltage is controlled in the power supply to the loads through the electric connection box. The electric connection box includes an electric connection box side input terminal connectable to the battery and an electric connection box side output terminal connectable to the loads. The power supply includes a power supply side input terminal that is directly connected to the electric connection box side input terminal and a power supply side output terminal that is directly connected to the electric connection box side output terminal. The power supply is directly supported by and fixed to the electric connection box.