The purpose of the present invention is realize the endoscope insertion part of miniaturization and obtain wide viewing angle. Providing a kind of endoscope lens optical assembly (1) sequentially to include successively includes: the first lens from object side, wherein from the concave surface that plano-concave lens (2) are formed towards image side Second lens by plano-concave lens (3) formed wherein concave surface towards object side Brightness iris (5) It is formed with the third lens (6) from plano-convex lens, wherein the plane surface is towards object side. Conditional formula (1-3) is to meet simultaneously below: 0.7≤fab/f≤0.9 ( 1 ) 1.7≤fe/fab≤2 ( 2 ) (3) 2≤fb/fa≤4 Here f total focal lengths Fathom is the focal length (2) of the first lens The focal length (3) of the second lens of fb Angle is the focal length (6) of the third lens Surprisingly synthesize (2) first lens of focal length and the second lens (3).
