Disclosed is a cable-type secondary battery, comprising: an inner electrode which includes an inner current collector and an inner electrode active material layer formed to surround the outer surface of the inner current collector; a separation layer formed to surround the outer surface of the inner electrode so that the inner electrode is inserted therein; and an outer electrode comprising: an outer electrode active material structure which is formed to surround the outer surface of the separation layer so that the separation layer is inserted therein, and which includes a porous polymer support and an outer electrode active material layer formed on at least one of the top surface and the bottom surface of the porous polymer support; and an outer current collector formed to surround the outer electrode active material structure so that the outer electrode active material structure is inserted therein.