PURPOSE: To analyze the breakdown point of a semiconductor device by providing optical microscopes, photoelectric converting tubes and an image processor.

CONSTITUTION: The voltage of a power source 12 is applied via a detecting needle to the circuit at the breakdown point of a sample 1. The light emitted by a broken p-n junction, etc., is detected on the front and rear by the IR microscopes 2, 3 and is made into the observable emitted light via IR/visual light converting filters 4, 5 and image multiplifer tubes 6, 7. This light is subjected to image pickup with image pickup tubes 8, 9 and is inputted to the image processor 10. The processor 10 respectively receive videos time-dividedly and process the respective video signals to the images corresponding to the circuit patterns of the sample 1 in the relations of the visual fields of the microscopes 2, 3 and the position of the sample 1, thereby forming the images superposed with the light-emitted images of the front and rear of the sample. The circuit pattern is then sent from an external memory 11 to a reading display device 12 and is displayed in the form of one video. The light-emitted image on the rear surface side is not shielded by Al wirings, etc., and the sufficient image signals are obtd. from the very slight light-emitted image. The breakdown point is distinctly discriminated and is easily analyzed.