The battery pack comprises: a bare cell including a can, wherein the can includes an opening on one side, and a cap plate sealing the opening of the can, wherein the cap plate has at least one groove formed on one surface; a circuit board including at least one lead tab. wherein the lead tab is coupled to the cap plate by a fixing body; and a coupling member coupled with the fixing body in the groove. The coupling member and the bare cell are made of different materials. Therefore, in the battery pack, the internal resistance between the bare cell and the protective circuit board does not increase, or the cover case is not separated when an external shock is applied.