A nitride semiconductor light-emitting device includes a substrate (101) made of silicon, a mask film (102) made of silicon oxide, formed on a principal surface of the substrate (101), and having at least one opening (102a), a seed layer (104) made of GaN selectively formed on the substrate (101) in the opening (102a), an LEG layer (105) formed on a side surface of the seed layer (104), and an n-type GaN layer (106), an active layer (107), and a p-type GaN layer (108) which are formed on the LEG layer (105). The LEG layer (105) is formed by crystal growth using an organic nitrogen material as a nitrogen source.