There is provided a semiconductor light emitting device including: a substrate and a nanostructures spaced apart from one another on the substrate. The nanostructures includes a first conductivity-type semiconductor layer core, an active layer, and a second conductivity-type semiconductor layer. A filler fills spaces between the nanostructures and is formed to be lower than the plurality of nanostructures. An electrode is formed to cover upper portions of the nanostructures and portions of lateral surfaces of the nanostructures and electrically connected to the second conductivity-type semiconductor layer.