Rectangular secondary battery

A rectangular secondary battery includes a rectangular casing that contains an electrode body, a sealing plate that seals an opening of the rectangular casing; a positive electrode tab group that is composed of a plurality of positive electrode tabs, a positive electrode terminal that is electrically connected to the positive electrode tab group and attached to the sealing plate, a second positive electrode current collector that is electrically connected to the positive electrode tab group and the positive electrode terminal, and a second insulator that is disposed between the sealing plate and the second positive electrode current collector. The sealing plate has a gas discharge valve. The sealing plate has a first recess. The second insulator has a first protrusion. In a transversal direction of the sealing plate, the first recess is displaced from a center of the sealing plate toward an end portion of the sealing plate.