Abstract: A microscope objective lens, sequentially from an object-side, comprises a first lens group constructed of a positive lens element, a second lens group constructed of a negative lens element, and a third lens group constructed of cemented lens elements consisting of a negative lens element and a positive lens element and exhibiting a positive refracting power on the whole. Further, the microscope objective lens system satisfies the following conditions:1.5<f/f.sub.1 <1.9-3.8<f/f.sub.2 <3.12.0<f/f.sub.3 <2.70.9<(d.sub.2 +d.sub.3 +d.sub.4 +d.sub.5)/f.sub.1 <1.215<n.sub.1 .multidot.f/d.sub.150<n.sub.2 .multidot.f/d.sub.3wheref : the focal length of the whole system,f.sub.1 : the focal length of the first lens group,f.sub.2 : the focal length of the second lens group,f.sub.3 : the focal length of the third lens group,d.sub.1 : the central thickness of the positive lens element in the first lens group,d.sub.

Abstract: An objective lens system for a microscope comprises, sequentially from an object side, a first lens group having positive refracting power, a second lens group shiftable in an optical-axis direction and a third lens group. The first lens group has a cemented lens component composed of a plano-convex lens element with its plane surface toward the object side and a meniscus lens element with its concave surface toward the object side. The second lens group has a first sub-group having the positive refracting power and a second sub-group having negative refracting power. The second sub-group of the second lens group has a negative meniscus lens element with its concave surface toward an image side. The third lens group has a meniscus cemented lens component with its concave surface toward the image side.