A battery module for installation in a vehicle comprising: a plurality of cylindrical battery cells, each of the plurality of cylindrical battery cells including a first electrode and a second electrode at both axial ends of the cylindrical battery; a battery cell holder configured to hold the plurality of cylindrical battery cells in a state where the first electrodes and the second electrodes are exposed to outside; a protective case configured to urge end faces on first-electrode sides of the plurality of cylindrical battery cells toward second-electrode sides of the plurality of cylindrical battery cells; a vent cover provided such that the battery cell holder is positioned between the protective case and the vent cover, the vent cover and the battery cell holder disposed such that a vent space in which gas discharged from an end face on the second-electrode side of the cylindrical battery cell flows is provided between the vent cover and the battery cell holder; at least one first-electrode bus bar being in contact with the first electrodes of the plurality of cylindrical battery cells such that at least two of the cylindrical battery cells are connected in parallel to each other; at least one second-electrode bus bar provided in the vent space and the at least one second-electrode bus bar being in contact with the second electrodes of the plurality of cylindrical battery cells such that at least two of the cylindrical battery cells are connected in parallel to each other, wherein the second-electrode bus bar comprises conductive plates integrated with each other by a resin material, wherein each conductive plate is provided with through-openings corresponding to the plurality of battery cells; and a support member disposed partially in the vent space and the support member being configured to support the second-electrode bus bar from the vent cover side wherein the support member includes a plurality of columnar portions disposed, at an interval, between the vent cover and the second-electrode bus bar wherein at least one columnar portion is provided near the peripheral edge of each through-opening. a plurality of cylindrical battery cells, each of the plurality of cylindrical battery cells including a first electrode and a second electrode at both axial ends of the cylindrical battery; a battery cell holder configured to hold the plurality of cylindrical battery cells in a state where the first electrodes and the second electrodes are exposed to outside; a protective case configured to urge end faces on first-electrode sides of the plurality of cylindrical battery cells toward second-electrode sides of the plurality of cylindrical battery cells; a vent cover provided such that the battery cell holder is positioned between the protective case and the vent cover, the vent cover and the battery cell holder disposed such that a vent space in which gas discharged from an end face on the second-electrode side of the cylindrical battery cell flows is provided between the vent cover and the battery cell holder; at least one first-electrode bus bar being in contact with the first electrodes of the plurality of cylindrical battery cells such that at least two of the cylindrical battery cells are connected in parallel to each other; at least one second-electrode bus bar provided in the vent space and the at least one second-electrode bus bar being in contact with the second electrodes of the plurality of cylindrical battery cells such that at least two of the cylindrical battery cells are connected in parallel to each other, wherein the second-electrode bus bar comprises conductive plates integrated with each other by a resin material, wherein each conductive plate is provided with through-openings corresponding to the plurality of battery cells; and a support member disposed partially in the vent space and the support member being configured to support the second-electrode bus bar from the vent cover side wherein the support member includes a plurality of columnar portions disposed, at an interval, between the vent cover and the second-electrode bus bar wherein at least one columnar portion is provided near the peripheral edge of each through-opening.