A immersion microscope objective includes: a first positive lens group that includes at least one positive single lens and a first cemented lens; a second positive lens group that includes a plurality of cemented lenses including a second cemented lens that is the closest to an object; a third negative lens group that includes a first lens component having a concave surface; and a fourth lens group that includes a second lens component that is the closest to the object, the second lens component having a concave surface, wherein the objective satisfies the following conditional expressions: 0.986≤NAob/N0≤0.995  (1) 0.0095≤1/(N1×ν1)≤0.015  (2) where NAob indicates a numerical aperture of the objective; N0, a refractive index that an immersion liquid has for an e line; N1, a refractive index that the meniscus lens has for the e line; ν1, an Abbe number that the meniscus lens has for a d line.