According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer, a light emitting unit, a second semiconductor layer, a reflecting electrode, an oxide layer and a nitrogen-containing layer. The first semiconductor layer is of a first conductivity type. The light emitting unit is provided on the first semiconductor layer. The second semiconductor layer is provided on the light emitting unit and is of a second conductivity type. The reflecting electrode is provided on the second semiconductor layer and includes Ag. The oxide layer is provided on the reflecting electrode. The oxide layer is insulative and has a first opening. The nitrogen-containing layer is provided on the oxide layer. The nitrogen-containing layer is insulative and has a second opening communicating with the first opening.