The present invention relates to a secondary battery and, in order to resolve a technical problem, provides a secondary battery, which blocks a leakage welding current when welding a current collecting plate to a can by coupling an insulating plate to the current collecting plate, and thus increases the welding strength between the current collecting plate and the can, improves welding strength distribution, and prevents damage between the current collecting plate and the can. To this end, disclosed is a secondary battery comprising: a cylindrical can having an opening; an electrode assembly which is accommodated in the opening of the cylindrical can and which is wound in a cylinder shape; a cap assembly which is electrically connected to the electrode assembly and which seals the cylindrical can; a current collecting plate for electrically connecting the electrode assembly with the cylindrical can; and an insulating plate inserted between the current collecting plate and the cylindrical can.