PURPOSE: To provide an inverted image lens which is well corrected of various aberrations and more particularly curvature of field, astigmatism, etc., as an observation optical system without degrading spherical aberrations, etc., as an illumination optical system.

CONSTITUTION: The first face 1a on the side of the eye to be examined of the inverted image lens 1 consisting of a single biconvex lens and the second face 1b on an inspector side are aspherical faces asymmetrical with each other. The displacements in the optical axis direction of both faces with respect to the displacement Y of the direction perpendicular to the optical axis with the vertex of the first face 1a and second face 1b as the original, respectively defined as X1 and X2 the focal length of the inverted image lens, defined as (f) and the refractive index to (d) rays, defined as (n), are -0.4≤Z≤0.2 in a range of 0<Y≤0.7×f when Z=(X1-X2)/(X1+X2)/n is set. The conditions Zmin-Zmax≤0.08 are satisfied when the values of Z are respectively defined as Z,, and Zmax, at Y=0.1×f and Y=0.7×f.