A battery module comprising: a plurality of battery cells each having terminals; and busbars each joining the terminals (1p, 1n) of the battery cells, each busbar having: a plurality of connection face portions (2c1, 2c2) each connected to a corresponding one of the terminals to be joined; a plurality of rising portions each rising from a corresponding one of the plurality of connection face portions; and a connection portion connecting the plurality of rising portions, the busbar comprising a copper portion including copper and an aluminum portion including aluminum, the copper portion and the aluminum portion being joined together, a joint between the copper portion and the aluminum portion being located on the connection face portions, the plurality of connection face portions having a pair of connection face portions disposed adjacently side by side on a plane, one of the connection face portions includes a dissimilar metal joining portion where the copper portion and the aluminum portion are overlapped for joining, the one of the connection face portions having: a flat portion including one of the copper portion and the aluminum portion, the flat portion being joined to one of the terminals of the battery cells; and a pair of arms (2f1) including the other of the copper portion and the aluminum portion, the arms projecting parallel to each other from one of the rising portions and being overlapped on the flat portion for joining. a plurality of battery cells each having terminals; and busbars each joining the terminals (1p, 1n) of the battery cells, each busbar having: a plurality of connection face portions (2c1, 2c2) each connected to a corresponding one of the terminals to be joined; a plurality of rising portions each rising from a corresponding one of the plurality of connection face portions; and a connection portion connecting the plurality of rising portions, the busbar comprising a copper portion including copper and an aluminum portion including aluminum, the copper portion and the aluminum portion being joined together, a joint between the copper portion and the aluminum portion being located on the connection face portions, the plurality of connection face portions having a pair of connection face portions disposed adjacently side by side on a plane, one of the connection face portions includes a dissimilar metal joining portion where the copper portion and the aluminum portion are overlapped for joining, the one of the connection face portions having: a flat portion including one of the copper portion and the aluminum portion, the flat portion being joined to one of the terminals of the battery cells; and a pair of arms (2f1) including the other of the copper portion and the aluminum portion, the arms projecting parallel to each other from one of the rising portions and being overlapped on the flat portion for joining. a flat portion including one of the copper portion and the aluminum portion, the flat portion being joined to one of the terminals of the battery cells; and a pair of arms (2f1) including the other of the copper portion and the aluminum portion, the arms projecting parallel to each other from one of the rising portions and being overlapped on the flat portion for joining.