To provide a vehicle control system capable of reliably detecting any voltage drop of a low voltage power supply.

In the system, part of electric devices are operated by allowing the supply of power from a low voltage power supply 262 to the electric devices without operating a converter 270 for dropping the discharge voltage of a high voltage power supply 250 under a specific condition even if a starting switch 304 is not operated. The system is constituted in the state so as to determine whether the terminal voltage of the low voltage power supply 262 is dropped according to whether the output voltage to the electric device, which is detected by a voltage sensor 290, is below threshold voltage.