A control apparatus for a vehicle generator includes a switch, a regulator, a fault condition detector, and a PWM signal generator. The switch is selectively turned on and off so as to intermittently excite the generator. The regulator controls on/off operation of the switch so as to bring an output of the generator into agreement with a target value. The fault condition detector detects a fault condition of the generator. The PWM signal generator generates and outputs a PWM signal that has a duty determined as a function of a duty of the on/off operation of the switch and a frequency determined based on if the fault condition of the generator is detected by the fault condition detector. Consequently, the control apparatus can inform an external control apparatus of the duty of the on/off operation of the switch and the fault condition of the generator with the single PWM signal.