According to one embodiment, a semiconductor light emitting device includes first and second electrodes, first, second and third semiconductor layers, and a light emitting layer. The first semiconductor layer of a first conductivity type is provided on the first electrode. The light emitting layer is provided on the first semiconductor layer. The second semiconductor layer of a second conductivity type is provided on the light emitting layer. The third semiconductor layer with low impurity concentration is provided on a part of the second semiconductor layer. The second electrode includes a pad section and a narrow wire section. The pad section is provided on the third semiconductor layer. The narrow wire section extends out from the pad section and includes an extending portion extending along a plane perpendicular to a stacking direction. The narrow wire section is in contact with the second semiconductor layer.