PURPOSE: To indicate the absolute direction of a specimen on a plane of image projection by indicating angular relation between the absolute direction of the specimen and an image on a display device while being interlocked with the value of ampere turn of the whole of both electron beam accelerating voltage and image forming electron lenses.

CONSTITUTION: The whole ampere turn AT of electron lenses 11 is detected by an ampere turn detector 15, the detected value is inputted into a rotational angle operating device 16, and the accelerating voltage u of an electron gun 12 is detected so that the detected value is also inputted into the rotational angle operating device 16. Signals from a rotational angle θobtained herein is inputted into an index generating device 17, and an index signal corresponding to the rotational angle θ is forwarded to a CRT display device 14 so that an arrow head 6 and the like are indicated on the CRT display screen. The signals for the rotational angle γ are also inputted into a LED selection device 18 to indicate LEDs 2 and 3 and the like disposed around the fluorescent screen 1 of an image observation chamber 13 wherein the LED corresponding to the angle θ is selected so as to be indicated. By this constitution, angular relation between the absolute direction of the specimen and the direction of the image of the specimen indicated on the fluorescent screen and the CRT display device can thereby be displayed for an operator.