Patent ID: 8164839

Claim:
An objective lens for an endoscope, comprising: a front lens group having a negative power; and a rear lens group having a positive power arranged such that an aperture stop is positioned between the front lens group and the rear lens group, wherein: the front lens group comprises at least a front-side negative lens and a front-side positive lens arranged in this order from an object side; the rear lens group comprises at least a rear-side positive lens and a cemented lens arranged in this order from the object side, the cemented lens being configured by cementing together a negative lens and a positive lens; and the objective lens satisfies following conditions: −4.5≦ f F /f≦− 2.0 (1); and 1.5≦ f RP /f≦ 2.5 (2) where f F (unit: mm) represents a focal length of the front lens group, f (unit: mm) represents a total focal length of the front lens group and the rear lens group, and f RP (unit: mm) represents a focal length of the rear-side positive lens.