An eyeground examining device for measuring the thickness of the optic nerve fiber layer of an eyeground easily and with high accuracy. A Stokes vector computing section (53) determines a Stokes vector according to the signal generated from an eyeground examining section (60). A phase difference distribution computing section (54) determines the phase difference distribution of the eyeground reflected light reflected from a specific region (Henles fiber layer ) of the eyeground according to the Stokes vector. An eye front part slow-axis computing section (55) and an eye front part phase difference computing section (56) determine the eyefront part component (the slow axis of the eye front part, the phase difference attributed to the eye front part) according to the phase difference distribution. An NFL component extracting section (57) extracts the NFL component from the polarized state of the eyeground reflected light according to the eye front part component. An NFL thickens computing section (58) computes the thickness of the optical nerve fiber layer according to the NFL component.
