Microscope objective lens, microscope optical system, and microscope device

A microscope objective lens, consisting of, in order from an object on an optical axis:

• a first lens group having a positive refractive power;
• a second lens group having a concave surface facing an image;
• and a third lens group having a concave surface facing the object,
• wherein the first lens group consists of a lens component having a positive refractive power,
• the third lens group consists of three or more lenses that include two negative lenses and one positive lens,
• at least one predetermined negative lens in the two negative lenses satisfies the following conditional expression,
• vdA<40
• where vdA:
• an Abbe number of the predetermined negative lens of the third lens group, and
• the microscope objective lens satisfies the following conditional expression,
• 0<θA−(0.6438−0.001682×vdA+0.007)
• where θA:
• a partial dispersion ratio of the predetermined negative lens of the third lens group, defined by the following expression assuming that a refractive index of the
• predetermined negative lens for g-line is ngA, a refractive index of the predetermined negative lens for F-line is nFA, and a refractive index of the predetermined negative lens for C-line is nCA,
• θA=(ngA−nFA)/(nFA−nCA).