<p>An electron microscope is provided with a phase plate (510) with a thickness that varies radially and adjusts the phase difference caused by the difference between electron beam paths due to the effect of spherical aberration when electron beams converge or form an image by a lens. Thus, coherence is improved by adjusting the phase difference caused by the difference between electron beam paths, so that a phase-contrast image of transmitted electrons can be obtained at a higher resolution.</p>
