The present invention relates to a cable-type secondary battery having a horizontal cross section of a predetermined shape and extending longitudinally, comprising: a core for supplying lithium ions, which comprises an electrolyte; an inner electrode, comprising an open-structured inner current collector surrounding the outer surface of the core, and an inner electrode active material layer formed on the surface of the inner current collector; a separation layer surrounding the outer surface of the inner electrode to prevent a short circuit between electrodes; and an outer electrode surrounding the outer surface of the separation layer and comprising an outer electrode active material layer and an outer current collector.The core disposed in the inner electrode having an open structure, from which the electrolyte of the core for supplying lithium ions can be easily penetrated into an electrode active material, thereby facilitating the supply and exchange of lithium ions.