BATTERY PACK

A battery pack includes: a plurality of battery cells arranged side by side in a first direction, each of the plurality of battery cells including a plurality of electrode terminals disposed side by side in a second direction orthogonal to the first direction; and a case member that accommodates the plurality of battery cells, the case member including a side surface portion extending in a direction orthogonal to the first direction or in a direction orthogonal to the second direction and a reinforcing rib provided on the side surface portion. The reinforcing rib extends in a third direction orthogonal to the first direction and the second direction or in a direction obliquely intersecting the third direction.