PURPOSE: To provide the astigmatism inspecting device which is not increased in the thickness in the direction where the optical axis for inspection of a vision tester extends.

CONSTITUTION: This device has a gear (lens holding plate) which is attachable and detachable in the direction orthogonal with the optical axis 0 for inspection, two pieces of cross cylinder lenses 10a, 10c which are juxtaposed in the attachment and detachment direction of this gear, are mounted to the gear 43 at the axes shifted by 90° from each other and are equal in optical characteristics and a changeover motor 40 which operates to attach and detach the above- mentioned gear 43.