1. An electron microscope including a plurality of detectors that are different in type, the detectors detecting signals generated by irradiation of a specimen with an electron beam, and signal switching means for switching the signals detected by the detectors, the electron microscope comprising: storage means for storing optimal observation conditions for each of the plurality of detectors; and control means for calling observation conditions stored in the storage means on the basis of the switching of the plurality of detectors and setting conditions of the electron microscope to the called observation conditions.