The purpose of the present invention is to allow a gas to be stably discharged from a cracking valve even if a battery lid is deformed toward a wound group side. In a rectangular secondary battery of the present invention, a curved surface portion of a flat wound group is disposed on the side of an opening of a battery can, and the opening is sealed with a battery lid having a cracking valve and a liquid injection port. At least a protruding portion having a facing surface positioned on a curved surface portion side with respect to the cracking valve is disposed on the battery lid between the liquid injection port and the cracking valve.