Electrical leakage determination system

An electrical leakage determination system determines if an electrical leakage occurs between each of power supply paths and a grounding section. The electrical leakage determination system includes a coupling capacitor with one end connected to an anode-side power supply path, a resistor connected to the other end of the coupling capacitor, and an oscillator connected to the resistor to output an AC voltage to the resistor. A determiner detects a voltage at a connection point located between the coupling capacitor and the resistor when the oscillator outputs an AC voltage to the resistor. The determiner determines if the electrical leakage occurs based on the detected voltage. The oscillator increases an absolute value of an AC voltage output during a preparation period provided prior to a detection timing when a voltage is detected at a connection point greater than an absolute value of an AC voltage output at the detection timing.