A secondary battery including an electrode assembly; first and second collector plates connected to respective first and second electrodes of the electrode assembly; a case accommodating the electrode assembly, the first collector plate, and the second collector plate; a cap plate sealing an opening of the case; a first electrode terminal electrically connected to the first collector plate and passing through the cap plate; a second electrode terminal electrically connected to the second collector plate and passing through the cap plate; and a short-circuit member electrically connected to the first collector plate and passing through the cap plate, the short-circuit member including a duct part in communication with an inside of the case; and a deformable part covering a top portion of the duct part and being deformable by a gas pressure inside the case to electrically connect the first electrode to the second electrode.