A light emitting device includes a light source and a light diverging unit including a first light diverging part and a second light diverging part including a bottom surface and a first light emitting surface connected by a side surface. The bottom surface defines a first receiving space for receiving the light source, the first light emitting surface defines a second receiving space communicating with the first receiving space, and the second receiving space comprises a first connecting surface. The second light diverging part is inserted into the second receiving space, and comprises a second light emitting surface and a second connecting surface. The second connecting surface fully contacts the first connecting surface, the second light emitting surface smoothly connects to the first light emitting surface. A refraction index of the first light diverging part is smaller than that of the second light diverging part.