The present invention comprises: an electrode assembly in which a separator is interposed in between a first electrode and a second electrode; a case for accommodating the electrode assembly; a cap plate for sealing an opening at the upper end of the case, wherein a first terminal electrically connected to the first electrode of the electrode assembly is integrally formed with the cap plate; at least one stepped portion protruding upward from the cap plate; and a plate terminal arranged on the exterior of the cap plate, wherein the plate terminal is provided with, on a bottom part thereof, a recessed groove having a size and a depth corresponding to the size and the height of the stepped portion. A secondary battery, according to one embodiment of the present invention, is provided with the protruding stepped portion on the cap plate so that the terminal can be fixed so as to prevent shifting to the left or to the right.