A light emitting device includes an active layer having quantum walls and quantum wells, a first conductive type semiconductor layer on one side of the active layer, a second conductive type semiconductor layer on the other side of the active layer, and an interfacial layer arranged between the active layer and the first conductive type semiconductor layer or between the active layer and the second conductive type semiconductor layer, wherein the interfacial layer includes barrier layers and basal layers provided between the barrier layers, wherein an energy bandgap of each of the barrier layers increases from the first conductive type semiconductor layer or the second conductive type semiconductor layer to an active layer direction linearly, and greatest energy bandgaps of the barrier layers are different from one another.