NOVELTY - The device (100) has a lead battery (10) for accommodating a lead battery cell (11) in an accommodating part i.e. lead electrolyte solution tank (36). An output terminal outputs electric power of the lead battery. A lead part (14) is connected to an auxiliary battery (20), the output terminal and the lead battery. A gravity center of the device is located in the accommodating part or another accommodating part i.e. storage space (35), located in a center part of a storage case (30) in which the two accommodating parts are connected with each other.    USE - Power supply device for use in a vehicle (claimed) e.g. large sized vehicle such as lorry, and for use as a battery for electrical equipments and an auxiliary machine battery.    ADVANTAGE - The lead part connects the lead battery and the auxiliary battery such that the gravity center of the device can be located in the accommodating parts located in the center part of the storage case in which the accommodating parts are connected with each other, so that dispersion in stress by position of a set screw can be made small and load of the device can be equally applied in arms, thus preventing need to loosen the set screw, need to vibrate the device and electrical storage element of the auxiliary battery from being damaged in an effective manner, carrying out the device with better balance without bringing discomfort, performing carry and attachment of the device to an engine compartment in an easier manner, adjusting weight of the auxiliary battery in an easier manner and heightening thermal radiation effect of the auxiliary battery.    DETAILED DESCRIPTION - The output terminal is a positive electrode side output terminal (12-plus) and a negative electrode side output terminal (12-minus). The auxiliary battery is a lithium ion secondary battery and a nickel-hydrogen battery.    DESCRIPTION OF DRAWING(S) - The drawing shows an exploded perspective view of a power supply device.    Lead battery (10)    Lead battery cell (11)    Negative electrode side output terminal (12-minus)    Positive electrode side output terminal (12-plus)    Lead part (14)    Auxiliary battery (20)    Storage case (30)    Storage space (35)    Lead electrolyte solution tank (36)    Power supply device (100)