The present invention relates to a cable-type secondary battery having a horizontal cross section of a predetermined shape and extending longitudinally, comprising: an inner electrode having an inner current collector and an inner electrode active material layer surrounding the outer 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 having an outer electrode active material layer and an open-structured outer current collector.