The electrical charging by a primary electronic is inhibited to produce a clear edge contrast from an observation specimen (i.e., a specimen to be observed), whereby the shape of the surface of a sample can be measured with high accuracy. An observation specimen in which a liquid medium comprising an ionic liquid is formed in a thin-film-like or a webbing-film-like form on a sample is used. An electron microscopy using the observation specimen comprises: a step of measuring the thickness of a liquid medium comprising an ionic liquid on a sample; a step of controlling the conditions for irradiation with a primary electron on the basis of the thickness of the liquid medium comprising the ionic liquid; and a step of irradiating the sample with the primary electron under the above-mentioned primary electron irradiation conditions to form an image of the shape of the sample.