To provide a light-emitting device, by which the light from light- emitting diodes which is a light source, is diffused effectively and is allowed to irradiate an object or objective person with high luminance.

The light-emitting device 1 includes a transparent, bar-shaped diffusion member 11 and a cap 31 having a light source 21 inside, comprising a plurality of light-emission diode 21a, 21b, and 21c, wherein insulating oil 3 is sealed into the cap 31, the inside of which is the passage of the light coming from the light source 21 into the diffusion member 11. A first reflection plate 17 is provided on the end surface of the diffusion member 11, the end surface being opposite to the light source 21, while a second reflection plate 39 is provided on the cap 31, the second reflection plate being opposite to the first reflection plate. On the sidewall of the diffusion member 11, a plurality of sidewall reflection plates 15 are arranged radially, wherein a space is formed between each sidewall reflection plate 15, a lens member 13a is integrally molded.