The endoscope (2) includes an observation optical system (41), two illumination optical systems (42, 43), a peripheral portion of the objective lens at the tip of the observation optical system, and a peripheral portion of the two illumination lenses Two inclined planes DS 11 and DS 12 formed in the middle of the two inclined planes DS 11 and DS 12 and extending in the direction of the distal end of the insertion section 12 between the peripheral edge of the objective lens and the peripheral edge of the two illumination lenses The height H 0 of the entrance surface IS of the objective lens of the observation optical system is higher than the height HBi of the two ridgeline portions AL 1 and AL 2, and the height H 0 of the two ridgeline portions AL 1 and AL 2, The exit surface ES of one illumination optical system is lower than the height HBi of the two ridgeline portions AL 1, AL 2. Furthermore, the two illumination lenses are arranged point symmetrically with respect to the central axis of the objective lens when the distal end portion (17) is viewed from the distal end direction.内視鏡(2)は、観察光学系(41)と、二つの照明光学系(42,43)と、観察光学系の先端の対物レンズの周縁部と二つの照明レンズの周縁部との間に設けられた二つの斜面部DS11、DS12と、二つの斜面部DS11、DS12の途中に形成され、対物レンズの周縁部と二つの照明レンズの周縁部との間に挿入部12の先端方向に突出するように形成された二つの稜線部AL1,AL2と、を備え、観察光学系の対物レンズの入射面ISの高さH0は、二つの稜線部AL1,AL2の高さHBiより高く、二つの照明光学系の出射面ESは二つの稜線部AL1,AL2の高さHBiより低い。さらに、二つの照明レンズは、先端部(17)を先端方向から見たときに対物レンズの中心軸に対し点対称に配設されている。
