ELECTRON MICROSCOPE

PURPOSE:To enhance the reliability of a test of a semiconductor wafer or the like with the use of an electron microscope, by removably attaching a magnetic shield of a cylindrical form or the like to the tip of a pole piece to block a magnetic field. CONSTITUTION:A magnetic shield 2 having a cylindrical form or the like is removably secured by an electroconductive tape 3 to the tip of a pole piece 1 for opposing an electron microscope to a sample 4 such as a semiconductor wafer to cause an electron beam 6 to penetrate it for a test. A magnetic field at a working distance is blocked by the magnetic shield 2 to make the test accurate. Magnetism is thus shielded by a removable simple means to enhance the reliability of the test with the electron microscope.