Apparatus for supplying power for a vehicle

An apparatus (1) for supplying power for a vehicle includes a first battery (B1), a second battery (B2), a switching device (RY1 and RY2), a monitoring device (9) and a control device (9). The first battery is electrically connected to load devices which are mounted on the vehicle. The second battery serves as a backup power source. The switching device switches the first and second batteries. The monitoring device monitors remaining capacity for each of the first and second batteries. When the control device determines that the remaining capacity of the second battery is less than the remaining capacity of the first battery based on information monitored by the monitoring device, the control device controls the switching device so as to conduct switching of the first and second batteries.