A electric wire connection structure includes a flat cable including a plurality of linear conductors and an insulator covering the linear conductors; a plurality of busbars for electrically connecting electrode terminals provided on two or more of battery cells stretched in a given direction among the plurality of battery cells stacked in the direction and included in a battery module, the electrode terminals being lined up in the direction; and connecting members provided for each combination of the linear conductors and the busbars to include a connecting member main body and a pressure welding blade portion connected to the connecting member main body, a pressure welding groove being formed on the pressure welding blade portion.