A secondary battery includes a bare cell having an electrode assembly. The electrode assembly has cathode plates, anode plates and separators insulating the cathode plates from the anode plates. The secondary battery also includes a can housing the electrode assembly, the can having an opening for receiving the electrode assembly and a cap assembly having a cap plate sealing an opening of the can, the cap plate having a terminal through-hole, an electrode terminal inserted into the terminal through-hole, and a gasket insulating the electrode terminal from the terminal through-hole. A protective circuit board is coupled to the bare cell and a molding resin molds the protective circuit board with the bare cell. The gasket includes a coupling extension constraining the molding resin at the cap plate.