Scanning electron microscope and sample observation method using the same

A scanning electron microscope having an X-ray detector for detecting an X-ray and a secondary electron detector for detecting secondary electrons, the microscope comprising:

• an object lens for generating a magnetic field, wherein the magnetic field is changed automatically in accordance with detection of the X-ray or the secondary electrons, and the magnetic field prevents an incidence of reflected electrons to the X-ray detector when the X-ray is detected.

A scanning electron microscope, an X-ray detector for detecting an X-ray and a secondary electron detector for detecting secondary electrons, the microscope comprising:

• an objective lens for focusing a primary electron beam or for preventing an incidence of reflected electrons, wherein a parameter related to the object lens is adjusted automatically in accordance with a change of X-ray detection and secondary electron detection.