A cable-type secondary battery is disclosed. The cable-type secondary battery includes electrodes, each of which includes a current collector having a horizontal cross section of a predetermined shape and an active material layer formed on the surface of the current collector. The electrodes extend in the lengthwise direction and are arranged in parallel. The current collector includes a polymer core and a metal coating layer formed on the surface of the polymer core. The use of the metal-coated polymer current collectors having high flexibility and conductivity makes the secondary battery highly flexible while maintaining the performance of the secondary battery. In addition, the cable-type secondary battery can be reduced in weight.