A battery pack includes: a cell stack; a first duct and a second duct configured to feed cooling air toward the cell stack; and a housing case. The first duct and the second duct extend in a first direction and are spaced apart from each other in a second direction, the first direction being parallel to a front-back direction of a vehicle in a mounted state in which the battery pack is mounted on the vehicle, the second direction being parallel to a width direction of the vehicle in the mounted state. The first duct is arranged on an outer side of the cell stack on one side in the second direction, and the second duct is arranged on an outer side of the cell stack on the other side in the second direction.