An electron beam apparatus comprises an electron beam source, a unit for irradiating an electron beam on a specimen, a detector for secondary electrons, an electrode for generating an electric field sufficient to draw out secondary electrons in a recess in the specimen from the recess, and a unit for generating a magnetic field for focusing secondary electrons drawn out of the recess. With this construction, the secondary electrons drawn out of the recess by the electric field reach the detector without being attracted by the electrode. By adopting this construction, a contact hole of high aspect ratio formed in a semiconductor device and having a small diameter and a large depth can be observed.