To specify an insulation deterioration part, even when insulation deterioration in a high voltage system and an inverter accident are caused concurrently, in a vehicle with the high voltage system including an inverter.

When there is an insulation deterioration log about a high voltage system and an inverter is defective (YES in S11) upon a Ready-OFF request (stop request of the high voltage system) (YES in S10), a control device performs discharge control to switch off one of the two system main relays and drop an inverter applied voltage to zero (S12). When the insulation deterioration changes from non-existence to existence before and after this discharge control (YES in S13), an alternating current unit is located as an insulation deterioration part (S14). When the insulation deterioration does not change from existence to non-existence before and after before and after this discharge control (YES in S15), a direct current unit is located as the insulation deterioration part (S16).