There is provided a nitride semiconductor light emitting device. A nitride semiconductor light emitting device according to an aspect of the invention may include: an n-type nitride semiconductor layer provided on a substrate; an active layer provided on the n-type nitride semiconductor layer, and including quantum barrier layers and quantum well layers; and a p-type nitride semiconductor layer provided on the active layer, wherein each of the quantum barrier layers includes a plurality of InxGa(1-x)N layers (0