PROBLEM TO BE SOLVED: To provide a deep part cross-sectional image of high sensitivity reduced in signal noise ratio, without being affected by the involuntary movement of the eyeball of a subject by disposing an optical element for diffraction preceding a scanning element for deflecting illumination light at least in one direction in irradiation beams. SOLUTION: The light of a short coherent light source 24 is made incident on an interferometer 22 and a receiver 26 arranged behind a spectroscope unit 25 detects measurement light returned from the eyeball 31. Parallel light from illumination is divided into a part Sko of collimated light beams and a part Sku of converging light beams at the time of reaching the optical element(DOE) 29 for the diffraction and both light beams Sko and Sku reach a reflection mirror 30 and two-dimensionally stereoscopically changed and image-formed in the direction of the eyeball 31 of the testee at an image formation lens part composed of lenses L1 and L2 . A part of the converging light beams reaching the surface of a cornea is dispersed or vertically reflected, passed through the lenses L1 and L2 and partially collimated again at the DOE 29.
INTERFERENCE MEASUREMENT DEVICE FOR EXAMINING OBJECT