This vehicle ground fault detection apparatus maintains a high level of insulation in an aluminum electrolytic capacitor to improve long-term reliability. This vehicle ground fault detection apparatus (10) detects a ground fault of a DC power supply by connecting the positive terminal or the negative terminal of a high-voltage power supply to one terminal of a coupling capacitor (15) provided with aluminum electrolytic capacitors (C1, C2, C3), applying a square-wave pulse signal to a measurement point at the other terminal of the coupling capacitor, and detecting a voltage signal generated at the measurement point. The vehicle ground fault detection apparatus (10) includes a charger and discharger (CPU 13) that charges and discharges the coupling capacitor when a ground fault of the DC power supply is not being detected.
