CONTROL DEVICE FOR ON-BOARD POWER SUPPLY UNIT, AND ON-BOARD POWER SUPPLY DEVICE

A control device for an on-board power supply unit includes a bypass conduction path that serves as a path for supplying power from a first position between power storage units in an on-board power supply unit to a second conduction path, a bypass relay that is interposed in the bypass conduction path, and a protective relay that is disposed between power storage units at a position farther toward a high-potential side than the first position. A control unit switches between first switching control for turning on the protective relay and turning off the bypass relay and second switching control for turning off the protective relay and turning on the bypass relay.