1. An electron microscope for picking up an observation image of a specimen based on an image observation condition, the electron microscope comprising: an image observation condition setting section for setting a plurality of different image observation conditions for a predetermined observation image picked up under a predetermined image observation condition; an observation image acquisition section for picking up a plurality of observation images based on the plurality of image observation conditions set through said image observation condition setting section; a second display section for simultaneously displaying the plurality of observation images picked up by said observation image acquisition section; an observation image selection section for selecting a desired observation image from among the observation images displayed on said second display section; and a first display section for displaying on an enlarged scale the observation image selected through said observation image selection section.