LEAKAGE DETECTION DEVICE AND POWER SYSTEM FOR VEHICLE

In leakage detection device, coupling capacitor has a first end connected to a current path of power storage unit connected to load in a state of being insulated from a ground. Voltage output generates a periodic voltage that changes periodically, and applies the periodic voltage to a second end of coupling capacitor via impedance element. Voltage output unit measures a voltage at a node between coupling capacitor and impedance element. Leakage determination unit estimates at least one of an upper peak value and a lower peak value at a certain time, calculates a peak-to-peak value between the upper peak value and the lower peak value with virtually aligned time axes, and determines presence or absence of a leakage between a current path of power storage unit and the ground.