PURPOSE: To improve the starting performance of an automobile and to attain stable operation of the same, by providing a calculating means for calculating a slip factor from the outputs of a means for detecting the speed of rotation of driving wheels and a means for detecting the speed of rotation of driven wheels, and also providing a slip-factor control means for decreasing the fuel supply rate.

CONSTITUTION: A fuel supply control means 4 produces a control output (m) corresponding to the output of a means 1 for detecting the position of an accelerator pedal. A slip-factor calculating means 5 calculates the slip factor from the outputs of a means 2 for detecting the speed of rotation of driving wheels and a means 3 for detecting the speed of rotation of driven wheels. A comparator 6 produces a signal (l) when the calculated slip factor is higher than a reference value (s). When the signal (l) is produced, that is, when the slip factor is high, a slip-factor control means 7 applies a fuel supply decreasing signal to a fuel supply means 8 independently of the signal (m). Thus, it is enabled to attain stable operation of a vehicle and to improve starting performance of the same on a road surface having a low friction factor.