ONBOARD BATTERY

An onboard battery mounted in a front section in a space located behind a rearmost seat of a vehicle includes: an assembly battery including electrode terminals arranged on a rear surface of the assembly battery in a vehicle frontward and rearward direction; and a battery case accommodating the assembly battery. A case rear-surface member forming a rear surface of the battery case is provided with a ridge portion that faces at least a part of a rear surface of the assembly battery in the vehicle frontward and rearward direction in a manner as to avoid the electrode terminals, the ridge portion rising toward the assembly battery. When the case rear-surface member is moved toward the assembly battery by an external force, the ridge portion comes into contact with the assembly battery before the case rear-surface member applies force to the electrode terminals.