The invention discloses a rectangular secondary battery (1) that is provided with a current blocking unit (60) which is arranged in a current path between a collector plate (21) that is connected to a wound electrode group (40) and an external terminal (61) that is disposed outside a battery container (2), and which cuts off the current path when the internal pressure within the battery container (2) rises. The current blocking unit (60) is provided with: a diaphragm (68) that is electrically connected to the external terminal (61) and is deformed when the internal pressure within the battery container (2) rises; a connection plate (24) that is connected to the diaphragm but is disconnected when the diaphragm is deformed; and a linking part (23) that links the connection plate and the collector plate with each other. The rigidity of the linking part (23) is lower than the rigidity of the collector plate (21).