The vehicle generator regulating apparatus includes a switching device operating to allow a field current to flow into a field coil of the vehicle generator from a vehicle battery when applied with a voltage signal, a drive circuit applying the voltage signal to the switching device when supplied with a control signal, and a control circuit supplying the control signal to the drive circuit when the output voltage is detected to be not above a predetermined voltage. The drive circuit includes a charge pump circuit stepping up a DC voltage supplied from the battery to generate the voltage signal by repeatedly performing a cycle of charging and discharging multiple capacitors in synchronization with an oscillation signal from an oscillator circuit. The drive circuit is configured to lower the frequency of the oscillation signal when the vehicle generator is in a low power output state.