Provided is a flexible light-emitting device including: a light-emitting complex medium including a polymer matrix, and a nano light-emitting material dispersed therein, the light-emitting complex medium generating light via application of an electric field thereto; a plurality of first fiber electrodes extending in a first direction and disposed within the light-emitting complex medium, wherein the plurality of first fiber electrodes are arranged along a first imaginary plane and are spaced apart from each other, wherein a first voltage is applied to the plurality of first fiber electrodes; and a plurality of second fiber electrodes extending in the first direction and disposed within the light-emitting complex medium, wherein the plurality of first fiber electrodes are alternated with the plurality of second fiber electrodes, wherein a second voltage different from the first voltage is applied to the plurality of second fiber electrodes.