Provided is a microscope objective lens that sufficiently corrects on-axis and off-axis chromatic aberrations and that has a long working distance. A microscope objective lens OL includes, in order from an object side, a first lens group G1 with positive refractive power and a second lens group G2 with negative refractive power. The first lens group G1 of the microscope objective lens OL includes a diffractive optical element GD including a diffractive optical surface D, and the diffractive optical element GD is arranged at a position closer to the image than a section where a diameter of a light flux passing through the first lens group G1 is the largest.