Provided is an endoscope capable of reducing transmission loss of illumination light. The illumination means 30 of the endoscope 2 includes a light source 31 of illumination light provided in the proximal portion 10, an illumination light transmission path 34 d provided in the insertion portion 10, a light source 31 and an illumination light transmission path 34 d And a light guide portion 33 provided. The light guide portion 33 surrounds the image light transmission tube 44 and is formed into an annular shape in which the cross sectional area orthogonal to the axis L is large on the proximal end side and small on the distal end side. The inner circumferential sce and the outer circumferential sce of the light guiding portion 33 constitute a reflecting sce for reflecting the illumination light, respectively. The space between the reflecting sces is an illuminating light transmission medium made of glass, translucent resin, or gas.照明光の伝送損失を小さくできる内視鏡を提供する。 内視鏡2の照明手段30は、手元部10に設けられた照明光の光源31と、挿入部10に設けられた照明光伝送路34dと、光源31と照明光伝送路34dとの間に設けられた導光部33とを含む。導光部33は、像光伝送管44を囲むとともに軸線Lと直交する断面積が基端側で大きく先端側で小さい環形状に形成されている。導光部33の内周面及び外周面がそれぞれ照明光を反射させる反射面を構成している。これら反射面どうしの間が、ガラス、透光性の樹脂、又は気体からなる照明光伝送媒体となっている。
