The present invention relates to a light emitting device. The light emitting device comprises a substrate, an N-type semiconductor layer formed on the substrate, and a P-type semiconductor layer formed on the N-type semiconductor layer, wherein a side surface including the N-type or P-type semiconductor layer has a slope of 20° to 80° from a horizontal plane. Further, a light emitting device comprises a substrate formed with a plurality of light emitting cells each including an N-type semiconductor layer and a P-type semiconductor layer formed on the N-type semiconductor layer, wherein the N-type semiconductor layer of one light emitting cell and the P-type semiconductor layer of another adjacent light emitting cell are connected to each other, and a side surface including at least the P-type semiconductor layer of the light emitting cell has a slope of 20° to 80° from a horizontal plane.