A light-emitting element 1 has a rod-shaped light-emitting element 3, an LED lamp 10, and a lens 20 for converging light from the LED lamp to an end face of the rod-shaped light-emitting element. The lens 20 has a scattering area around the centerline of an extremity thereof, and the scattering area scatters light in proximity to the centerline, thereby irradiating an inner peripheral surface of the rod-shaped light-emitting element 3 with the light.