A rectangular secondary battery according to the present invention includes an electroconductive member, a first insulating member, a pressure-sensitive circuit breaker that includes an inversion plate and a positive electrode current collector. The electroconductive member has a first outer side surface and a second outer side surface that face away from each other. The first insulating member includes a pair of short side walls. One of the short side walls is located outside of the first outer side surface and presses the first outer side surface toward the second outer side surface. The other short side wall is located outside of the second outer side surface and presses the second outer side surface toward the first outer side surface.