The objective lens

PURPOSE: To provide an objective lens which has high power, a high NA, and a long operation distance by specifying the constitution of lens groups, has various aberrations, specially, a chromatic aberration compensated over a wide range without using too many cemented lenses or too much abnormality dispersion glass, and has an exit pupil position made uniform. CONSTITUTION: The objective lens has a lens group consisting of a two diffraction optical elements and at least one cemented lens between them. This objective lens has a 1st group G1 which includes a meniscus lens having a concave surface on the object side and has positive power on the whole and a 2nd group G2 which includes the two diffraction optical elements and at least one cemented lens in order from the object side, and satisfies a condition of 0.5 0.8, etc. Here, R is the image-side radius of curvature of the meniscus lens, (t) is the thickness, and Dd and D are marginal luminous flux diameter and maximum marginal luminous flux diameter on the respective diffraction optical element surfaces.