ONBOARD POWER-SOURCE DEVICE

Provided is an onboard power-source device wherein current does not easily stray between a main battery and an auxiliary battery that supply power to the outside. The onboard power-source device comprises an onboard main battery, an onboard auxiliary battery, a switch, a main power-supply path, an auxiliary power-supply path, a relay, and wiring. The switch has a first end, which is connected to the main battery and to the main power-supply path, and a second end, which is connected to the auxiliary battery. The relay has a first contact, which is connected to the auxiliary power-supply path,and a second contact, which is connected to the second end. The first contact and the second contact form a pair. The wiring connects the first end and the first contact and is a connection path thatsupplies power from the main battery to the auxiliary power-supply path. 提供种在对外部供电的主电池与副电池之间不易发生电流的蔓延的车载用电源装置。车载用电源装置具备车载用的主电池、车载用的副电池、开关、主供电路径、副供电路径、继电器和布线。开关具有连接于主电池以及主供电路径的第端和连接于副电池的第二端。继电器具有连接于副供电路径的第接点和连接于第二端的第二接点。第接点与第二接