A battery module has battery cells. The battery cells are arranged side by side while being separately held by battery holders. The battery cells are connected in series with bus bars. Each bus bar has a bent portion. Each battery holder includes a protruding wall that is provided between connection terminals adjacent to each other in the direction in which the battery cells are arranged. The protruding walls protrude further than the connection terminals in the direction in which the connection terminals protrude from the cases.