A vehicle control system has a battery mounted to a vehicle, a vehicle alternator charging the battery, a battery current detection device detecting a charging/discharging current of the battery, a voltage regulation device regulating an output voltage of the vehicle alternator to a specified output voltage, and a temperature sensor mounted to the inside of the battery current detection device. One terminal of a shunt resistance is connected to a negative terminal of the battery through a battery clump, and the other terminal of the shunt resistance is grounded. The temperature sensor is placed close to the shunt resistance. This structure enables the temperature sensor to detect the temperature of the battery with a high accuracy while considering the temperature characteristics of the shunt resistance.