Abstract: A battery pack includes a pack housing having an internal space in which a plurality of battery modules are installed or a plurality of battery cells are installed directly without being modulized; and a venting member installed in the pack housing and configured to discharge gas generated in the internal space externally, wherein the venting member is configured such that a cross-sectional area A1 of an outlet side of the venting member connected to an external space of the pack housing is smaller than a cross-sectional area A1 of an inlet side of the venting member connected to the internal space.