An objective lens for an endoscope, comprising: a first lens group having a negative power; an aperture stop; and a second lens group having a positive power, wherein the first lens group, the aperture stop and the second lens group are arranged in this order from an object side, wherein: the first lens group comprises at least a negative front group lens having a concave surface facing an image side, and a positive front group lens having a convex surface facing the image side, the negative front group lens and the positive front group lens being arranged in this order from the object side; the second lens group comprises at least a positive rear group lens having a convex surface facing the image side and a cemented lens formed by cementing together a negative lens and a positive lens, the positive rear group lens and the cemented lens being arranged in this order from the object side; and when a focal length of the first lens group is defined as f F (unit: mm), a total focal length of the first lens group and the second lens group is defined as f (unit: mm), a radius of curvature of an object side surface of the negative front group lens is defined as R 1 (unit: mm), and a radius of curvature of an image side surface of the negative front group lens is defined as R 2 (unit: mm), the objective lens for an endoscope satisfies following conditions and: − 3.5 ≤ f F / f ≤ − 1.5 1.3 ≤ SF ≤ 1.6 where SF=(R 1 +R 2)/(R 1 -R 2), characterized in that, when a maximum image height in an imaging plane is defined as y, an intermediate image height lower than the maximum image height y is defined as y i, a half view angle corresponding to the maximum image height y is defined as ω m, and a half view angle corresponding to the intermediate image height y i is defined as ω i, the objective lens for an endoscope satisfies a following condition: 1.3 × sin ω i / 1.3 ≤ y i / f ≤ 3.0 × sin ω i / 3.0 where 60° ≤ ω i ≤ ω m. a first lens group having a negative power; an aperture stop; and a second lens group having a positive power, wherein the first lens group, the aperture stop and the second lens group are arranged in this order from an object side, wherein: the first lens group comprises at least a negative front group lens having a concave surface facing an image side, and a positive front group lens having a convex surface facing the image side, the negative front group lens and the positive front group lens being arranged in this order from the object side; the second lens group comprises at least a positive rear group lens having a convex surface facing the image side and a cemented lens formed by cementing together a negative lens and a positive lens, the positive rear group lens and the cemented lens being arranged in this order from the object side; and when a focal length of the first lens group is defined as f F (unit: mm), a total focal length of the first lens group and the second lens group is defined as f (unit: mm), a radius of curvature of an object side surface of the negative front group lens is defined as R 1 (unit: mm), and a radius of curvature of an image side surface of the negative front group lens is defined as R 2 (unit: mm), the objective lens for an endoscope satisfies following conditions and: − 3.5 ≤ f F / f ≤ − 1.5 1.3 ≤ SF ≤ 1.6 where SF=(R 1 +R 2)/(R 1 -R 2), characterized in that, the first lens group comprises at least a negative front group lens having a concave surface facing an image side, and a positive front group lens having a convex surface facing the image side, the negative front group lens and the positive front group lens being arranged in this order from the object side; the second lens group comprises at least a positive rear group lens having a convex surface facing the image side and a cemented lens formed by cementing together a negative lens and a positive lens, the positive rear group lens and the cemented lens being arranged in this order from the object side; and when a focal length of the first lens group is defined as f F (unit: mm), a total focal length of the first lens group and the second lens group is defined as f (unit: mm), a radius of curvature of an object side surface of the negative front group lens is defined as R 1 (unit: mm), and a radius of curvature of an image side surface of the negative front group lens is defined as R 2 (unit: mm), the objective lens for an endoscope satisfies following conditions and: − 3.5 ≤ f F / f ≤ − 1.5 1.3 ≤ SF ≤ 1.6 where SF=(R 1 +R 2)/(R 1 -R 2), characterized in that, when a maximum image height in an imaging plane is defined as y, an intermediate image height lower than the maximum image height y is defined as y i, a half view angle corresponding to the maximum image height y is defined as ω m, and a half view angle corresponding to the intermediate image height y i is defined as ω i, the objective lens for an endoscope satisfies a following condition: 1.3 × sin ω i / 1.3 ≤ y i / f ≤ 3.0 × sin ω i / 3.0 where 60° ≤ ω i ≤ ω m.