The present invention relates to an inspection system for transparently taking an image of inside of a semiconductor device to analyze anomalous occurrence. First, image data obtained under infrared ray illumination are converted into a first left-to-right reversed image data in which the obtained image data are reversed left to right and the first left-to-right reversed image data are stored. Next, very weak light emitted from an anomalous portion when the semiconductor device is biased is picked up under no illumination. Then, image data of very weak light is converted into a second left-to-right reversed image data in which the image data of weak light are reversed left to right. The first and second left-to-right image data are superimposed to superimpose the image specifying the anomalous location on an image of chip patterns in the semiconductor device and the superimposed image is displayed. Further, in the infrared-ray epi-irradiation means, an optical filter made of the same material as that of the semiconductor device to be measured is used to form infrared rays for illumination, so that when the back surface of the semiconductor device is irradiated with infrared rays produced by the optical filter, light having a short wavelength which is easily reflected on the surface of the semiconductor device is interrupted and infrared rays having high transmittance against the semiconductor device can be obtined.