A battery module ensures safety when a thermal event occurs in the battery module. A battery module includes a cell assembly including one or more battery cells, a module case having an inner space in which the cell assembly is accommodated, the module case including a venting hole through which venting gas generated from the cell assembly is discharged, and a venting unit attached to an outer side of the module case, and configured to allow venting gas discharged from the venting hole to be introduced and discharged to an outside and configured to switch a flow direction of the venting gas to an opposite direction.