An ECU executes a program including a step of turning on an SMRP and an A-SMRP if an ignition switch is turned on; a step of detecting voltage values VB(1) and VB(2) of running batteries when VH is detected and if VH is higher than 180 V; a step of detecting that SMRP connected to the running battery is welded, if VB(1) is higher than 150 V; and a step of detecting that A-SMRB connected to the running battery is welded, if VB(2) is higher than 150 V.