An electrical leakage determination device includes: a capacitor connected to a battery; a detection resistor connected to the capacitor; a detection unit detecting a voltage value at a connection point between the detection resistor and the capacitor; a low amplitude voltage application unit applying a low amplitude voltage to the detection resistor every driving cycle; a high amplitude voltage application unit applying, before the application of the low amplitude voltage to the detection resistor, a high amplitude voltage to the detection resistor. The device determines whether there is electrical leakage between the power supply circuit and the ground based on a peak value of the voltage value detected when the low amplitude voltage is being applied, and changes a time integral value of the high amplitude voltage applied to the detection resistor based on a change in the voltage value detected when the low amplitude voltage is being applied.