A secondary battery has a depression having a thickness less than that of other portions of the periphery of a cap plate or a can. The depression includes a rupture section having a smallest thickness in the depression and further includes wrinkles between the rupture section and the periphery of the depression. Furthermore, the secondary battery is manufactured by a method including: a first coining step of forming the thickness of some portions of the cap plate or the can to be less than that of other peripheral portions thereof; a second coining step of forming wrinkles on the periphery of some portions where the first coining has been performed; and a third coining step of forming a rupture section having the smallest thickness in the depression on an inner side of the wrinkles.