An objective lens for an endoscope performs focusing from a farthest point object to a nearest point object by moving, along optical axis Z, at least one lens group excluding a most object-side lens group. The following conditional formulas (1) and (2) are satisfied: 1.2&nlE；ft/fw&emsp；&emsp；(1)； and 0.0<；(fm&minus；fw)/(ft&minus；fw)&nlE；0.5&emsp；&emsp；(2), where ft: a focal length of an entire system when the objective lens has been focused on the nearest point object, fw: a focal length of the entire system when the objective lens has been focused on the farthest point object, dt: an object distance to the nearest point object, dw: an object distance to the farthest point object, dm, which is represented by dm=(2×dw×dt)/(dw+dt): an object distance to a middle point object, and fm: a focal length of the entire system when the objective lens has been focused on the middle point object.
