Abstract: A tilt stage that tilts about Y axis perpendicular to the optical axis of an electron beam which is called "the Z axis" herein is mounted to the front cover of a specimen chamber. A Z-axis stage capable of moving in the direction of Z axis and an X-axis stage capable of moving in the direction of X axis perpendicular to Y and Z axes are mounted on the tilt stage. A specimen holder for holding a specimen can be located at any desired position relative to the electron beam by the movements of these stages. Two driving shafts are disposed concentrically about the Y axis, i.e., their common axis. Driving mechanisms for independently driving the driving shafts along the Y axis are mounted to the front cover of the specimen chamber. The movements of the driving shafts are transmitted to the Z-axis stage and the X-axis stage via two levers whose pivots are supported on the tilt stage.