Microscope objective lens and microscope apparatus

An infinity-corrected microscope objective lens converting light from an object into parallel light, comprising,

• in order from the object on an optical axis:
• a first lens group having a positive refractive power;
• and a second lens group having a positive refractive power,
• wherein an intermediate imaging plane on which an image is formed with the light from the object is formed between the first lens group and the second lens group or in a lens closest to an image in the first lens group,
• wherein the first lens group includes at least one lens having a concave-shaped lens surface facing the intermediate imaging plane, and
• the following conditional expression is satisfied,
• −0.2<f×NA/TL<−0.05
• 0.1<WD/r1<2.0
• where f:
• a focal length of the microscope objective lens,
• NA:
• an object-side numerical aperture of the microscope objective lens,
• TL:
• a distance on the optical axis from a most object-side lens surface of the microscope objective lens to a most image-side lens surface of the microscope objective lens
• WD:
• a distance on the optical axis from an object surface to the most object-side lens surface of the microscope objective lens, and
• r1:
• a radius of curvature of a concave-shaped lens surface of a lens having a smallest radius of curvature of the concave-shaped lens surface, among the at least one lens of the first lens group.