A semiconductor light emitting device includes a substrate, a semiconductor laminate having a base semiconductor layer, a first conductivity-type semiconductor layer, an active layer, and a second conductivity-type semiconductor layer sequentially formed on the substrate and divided by an isolation region to provide a plurality of light emitting cells, an intermediate separation layer interposed between the base semiconductor layer and the first conductivity-type semiconductor layer, a plurality of first and second electrodes connected to the first and second conductivity-type semiconductor layers, respectively, of the plurality of light emitting cells, and a wiring unit connecting the first and second electrodes of different light emitting cells.