A fault detection system is provided which includes power lines connecting between a DC power supply and electric equipment, switches respectively provided to the power lines, a capacitor connected to the power lines at a position where a distance to the electric equipment is shorter than a distance between the switches and the electric equipment, a charging unit charging the capacitor before the switches are turned on, a detection section connected to the power line at a connecting point where a distance to the DC power supply is shorter than a distance between the switches and the DC power supply, and detecting a change in an electric potential of the connecting point, and a determination section determining whether a short-circuit fault has occurred in any one of the switches based on a difference in the electric potential of the connecting point between before and after the capacitor is charged.