A battery pack includes a plurality of stacked single battery cells, a case for housing the plurality of stacked single battery cells, and a vehicle body fastening member for fastening the case to a vehicle body frame, wherein the vehicle body fastening member is provided separately from case, is connected to at least one of two side wall parts opposing each other in a width direction of the case by a hooking structure facing an upper surface and a lower surface of the side wall part, and is provided independently at a plurality of arbitrary positions along a length direction of the case.