Disclosed in the present invention is a secondary battery having a safety vent integrally formed with a side wall part of a case thereof whereby the secondary battery is improved in safety and has the effect of reducing manufacturing cost and simplifying process. As an example, disclosed is a secondary battery comprising: an electrode assembly; a case for receiving the electrode assembly; and a cap plate for covering an opened opening of the case, wherein the case includes two pairs of side wall parts, the side wall parts in each pair facing each other, and a bottom part perpendicular to the side wall parts, and a safety vent is integrally formed with an edge part of one region selected from the side wall parts and the bottom part.