A light emitting device including a light emitting structure comprising a plurality of light emitting regions comprising a first semiconductor layer, an active layer and a second semiconductor layer, a first electrode unit disposed on the first semiconductor layer in one of the light emitting regions, a second electrode unit disposed on the second semiconductor layer in another of the light emitting regions, and at least one connection electrode to sequentially connect the light emitting regions in series, wherein the light emitting regions connected in series are divided into 1st to ith light emitting region groups and areas of light emitting regions that belong to different groups are different (where 1