Provided is a battery pack having a plurality of single cells connected to one another, the battery pack being capable of preventing a temperature elevation caused by a short-circuit current that is generated when a sharp conductive foreign matter penetrates each of the single cells. The battery pack disclosed herein is a battery pack that has single cells arranged adjacent to each other, these adjacent single cells being electrically connected in series. In this battery pack, among a plurality of positive and negative electrode sheets configuring layered electrode bodies of the respective single cells, a negative electrode sheet is disposed on the lowermost stream side in the arrangement direction, and this negative electrode sheet disposed on the lowermost stream side is configured to have a lower electric resistance than the other negative electrode sheets configuring the layered electrode bodies and to break at a temperature lower than the temperatures at which the other negative electrode sheets break.