A high-reliability prismatic secondary battery with a current interruption mechanism that is unlikely to be damaged even if the battery is subjected to shock is provided. The prismatic secondary battery includes a second insulating member having a first through-hole, the second insulating member being arranged between a first region of a positive electrode collector and an inversion plate. The first region of the positive electrode collector and the inversion plate are electrically connected to each other through the first through-hole. The second insulating member has a plurality of fixing pawl portions. The fixing pawl portions are hooked and fixed to a fixing portion formed on the outer surface side of the conductive member.