aberration is hardly affected by manufacturing errors, and provides an endoscope objective lens small variation in curvature during focusing. In order from the object side, a front group having a negative refractive power (GF), and the group (GR) after having an aperture stop (AS) and positive refractive power, of the front group and the (GF) and the rear group (GR) and a focusing lens (Lf) having a negative refractive power which can be inserted into and removed from the optical path between, the focus lens (Lf) is inserted into the optical path in the ordinary observation state, short near the working distance than the normal observation state to provide an endoscope objective lens to be retracted from the optical path (1) at a distance observation state.収差が製造誤差による影響を受けにくく、フォーカスの際の像面湾曲の変動が小さい内視鏡対物レンズを提供する。物体側から順に、負の屈折力を有する前群(GF)、明るさ絞り(AS)および正の屈折力を有する後群(GR)と、前群(GF)と後群(GR)との間の光路に挿脱可能な負の屈折力を有するフォーカスレンズ(Lf)とを備え、該フォーカスレンズ(Lf)が、通常観察状態において光路に挿入され、通常観察状態よりも作動距離の短い近距離観察状態において光路から退避される内視鏡対物レンズ(1)を提供する。
