A connecting structure for a secondary battery for electrically connecting a core pack where two or more unit cells are electrically connected and a protection circuit module made of the unit cells of the core pack and a PCB substrate. The connecting structure includes a metal plate having an electrode connecting unit connected to an electrode of each unit cell of the core pack and a circuit connecting unit connected to the protection circuit module; and a circuit terminal unit electrically connected to the circuit connecting unit by being located in a connection hole formed in the PCB substrate of the protection circuit module so that the upper and lower portions of the PCB substrate communicate with each other. The circuit connecting unit is coupled and electrically connected to the circuit terminal unit by means of a connection method which allows selective connection and separation.