PURPOSE: To irradiate TEM wave satisfactory in quality as an article to be inspected by making the first calibrating measurement for measuring the reflection of an absorber wall, removing a comparative absorber in the inspecting region of the absorber wall, and making the second calibrating measurement for measuring the reflection of a metallic wall behind it.

CONSTITUTION: The first calibrating measurement is made. At this time, on all absorber walls 5, namely, body walls including an inspecting region, a comparative absorber 13 is fitted. Abrupt side edge pulse waves are irradiated, and scattered waves generated by incompleteness are detected. Next, the second calibrating measurement is made. At this time, the absorber 13 is removed in the region so that a metallic wall behind it may appear. Abrupt side edge pulse waves are irradiated, and scattered waves generated by a metallic wall 8 are detected. Comparative measurement is then conducted, and at this time, an inspecting absorber 14 is fitted in the region. Abrupt side edge pulse waves are irradiated, and scattered waves deviated from an absorber 14 are detected.