PURPOSE: To easily analyze the dislocation state of the crystal of a sample by calculating and displaying the difference between the two scattered images obtd. by projecting IR laser beams from two directions to one sample so that the scattered image stressed of the dependency on oritation is obtd.

CONSTITUTION: The IR laser beam IR is perpendicularly projected to the end face Ta of the square sample Ta and the entire area is scanned in a direction Y. The image data of the scattered images is stored in an image memory device 14. A rotary sample stage 1 and an IR vidicon 3 are then rotated 90° in a direction Q and the image data of the scattered images in said direction is stored in the memory 14. The difference between the two sets of the image data in the device 14 is computed by the command of an arithmetic command circuit 16 and the image by the data after the computation is displayed on a CRT 13. The image stressed of the scattered image by a scattering body having the dependency on the orientation is thereby obtd. and the analysis of the dislocation state of the crystal in the sample is facilitated.