A battery pack includes a plurality of prismatic secondary batteries with spacers each interposed therebetween. The prismatic secondary batteries each include a flat wound electrode body that is formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween; a prismatic outer body that houses the wound electrode body; and a sealing plate that seals an opening of the flat wound electrode body. The wound electrode body has a wound positive electrode core-exposed portion at one end portion and a wound negative electrode core-exposed portion at the other end portion. A positive electrode current collector is joined to the positive electrode core-exposed portion to form a positive electrode-joined portion, and a negative electrode current collector is joined to the negative electrode core-exposed portion to form a negative electrode-joined portion.