In both cases of normal observation and close observation, sufficient observation is performed while securing sufficient light distribution. An observation optical system 1 for performing magnified observation in proximity to a subject and a plurality of illumination optical systems 2 for irradiating illumination light to the subject, wherein the distance between the distal end surface of the insertion portion and the subject is 1.5 mm to 2.5 mm When the maximum brightness within the observation viewing angle is ITM, Center brightness is ITCAt the time of normal observation in which the distance between the distal end surface of the insertion portion and the subject is 50 mm, the center brightness is IWC, The brightness at the position of 80% of the maximum field angle is IWS, The endoscope satisfies the following conditional expression. 0.3 <；ITC/ ITM<；0.45 ... (1) 0.15 <；IWS/ IWC<；0.25 (2) 0.3 <；fLFT/ LIH<；0.6 (3) However, fLIs the focal length of the entire system of the illumination optical system, fTIs the focal length of the entire system at the maximum magnification of the observation optical system, LIs the outer diameter of the most object side lens of the illumination optical system, IHIs the maximum image height of the observation optical system.通常観察時と近接観察時のいずれにおいても、十分な配光を確保して良好な観察を行う。 被写体に近接して拡大観察を行う観察光学系１と、被写体に照明光を照射する複数の照明光学系２とを備え、挿入部先端面と被写体との距離が１．５ｍｍ～２．５ｍｍである近接観察時において観察視野角内における最大明るさをＩＴＭ、中心明るさをＩＴＣとし、挿入部先端面と被写体との距離が５０ｍｍである通常観察時において中心明るさをＩＷＣ、最大画角の８０％の位置の明るさをＩＷＳとしたとき、以下の条件式を満たす内視鏡である。 ０．３＜ＩＴＣ／ＩＴＭ＜０．４５ … （１） ０．１５＜ＩＷＳ／ＩＷＣ＜０．２５ … （２） ０．３＜ｆＬｆＴ／φＬＩＨ＜０．６ … （３） 但し、ｆＬは照明光学系の全系の焦点距離、ｆＴは観察光学系の最大拡大時の全系の焦点距離、φＬは照明光学系の最も物体側のレンズの外径、ＩＨは観察光学系の最大像高である。
