Provided is a light emitting device having an inner-propagation-medium which caused directivity-to-optical-axis-direction to be relaxed. Light of a LED travels in the inner-propagation-medium, being emitted from an inside area of or outside area in a lens surface directly or via an inclined reflection face. A light emitter provides an output light having an intensity profile with a half-intensity-angular-range not greater than 20.degree., which expresses directivity of the output light. The outside area in the lens surface performs a traveling-direction-expanding-function which is not only relatively intensive as compared that performed by the inside area in the lens surface, and but also relatively intensive as compared that performed in an imaginary case where the outside area gives a planar surface perpendicular to an optical axis. The half-intensity-angular-range of the intensity profile of the light emitting device is not smaller than 30.degree. with respect to the optical axis and not greater than 70.degree.. The lens face may be formed of one or more convex surfaces in the outside area.