A vehicle controlling system includes a high-voltage circuit including a motor for driving a vehicle and a generator driven by an engine; an intermediate-voltage circuit including a battery and having a potential lower than the potential of the high-voltage circuit; a low-voltage circuit having a potential lower than the potential of the intermediate-voltage circuit, accessories being disposed to the low-voltage circuit; a transformer disposed between the high-voltage circuit and the intermediate-voltage circuit; and a down converter disposed between the intermediate-voltage circuit and the low-voltage circuit. The controlling system further includes a generator controller to control the generator such that the generator generates power equal to or higher than the sum of power consumed by the motor and power output from the transformer to the intermediate-voltage circuit at a temperature of the battery lower than a predetermined temperature, and a transformer controller to control the transformer such that the transformer outputs power equal to or lower than power output from the down converter to the low-voltage circuit at a temperature of the battery lower than the predetermined temperature.