In electron holography observation using a transmission electron microscope, searching of conditions of an electron optical condition which are necessary for realizing a requested spatial resolution is sophisticated and for persons unaccustomed to operation of the electron microscope, the observation is time consuming work. In addition to the fundamental electron microscope proper, an input unit for inputting a spatial resolution requested in the holography observation, a calculation unit for calculating positions of electron biprism and specimen necessary for realizing the requested spatial resolution from the inputted value and parameters characteristic of the device and mechanisms for moving the two positions for realizing the obtained calculation results are provided.