A battery pack includes: a plurality of battery modules each including a plurality of battery cells arranged side by side in a first direction; and a cooling mechanism having passages arranged adjacent to the plurality of battery modules to conduct a heat transfer medium to cool the plurality of battery modules, the cooling mechanism including: a plurality of inflow tubes arranged adjacent to a center line extending through centers of the plurality of battery modules in the first direction, the plurality of inflow tubes having first distal ends to receive heat transfer medium and second distal ends to discharge heat transfer medium; and a plurality of outflow tubes connected to the second distal ends of the plurality of inflow tubes to discharge heat transfer medium therefrom, the plurality of outflow tubes being disposed in a position further outwardly from the center line than the plurality of inflow tubes.