A method of manufacturing a nanostructure semiconductor light emitting device may include: stacking a mask layer on a conductive base layer and forming a through hole penetrating the mask layer; growing a nanocore through the through hole from the conductive base layer using precursor gas including indium-containing precursor gas in a mixed gas atmosphere of nitrogen and hydrogen; removing the mask layer; and sequentially growing an active layer and a first conductivity type semiconductor layer on a surface of the nanocore.