The electron microscope provides sufficient leg space for an observer sitting in a chair in a working posture and allows concentrated observation and swift operation of the electron microscope without burdening the observer. An electron gun column is supported on a support structure formed in a rectangular parallelepiped. The electron gun column, a column evacuation device and a viewing chamber are mounted on the dampers on the support structure through a vibration plate. The table is mounted on the support structure through table supports provided on the top surface of the support structure. Further, the table has an opening at a location corresponding to the viewing chamber so that the table and the viewing chamber, both mounted on the support structure, are not in contact with each other. The layout of the operation panel divides the operation devices of the electron microscope into a group of devices that are frequently reached by touch and operated during observation and a group of devices that are not frequently used during observation. The former group is arranged in arc areas within reach of the operator's arms when pivoted about the elbows as the operator rests his arms naturally on the operation table. The latter group is classified according to the functions performed and is arranged in positions that are behind the arc areas of pivoting arms and are easily recognized visually.