Abstract: An electron beam apparatus comprises, inside of an objective lens for focussing a primary electron beam e1 and irradiating it on a sample surface, a secondary electron energy analyzer having a retarding mesh electrode for analyzing the energy of a secondary electron e2 emitted from a point on the sample surface at which the primary electron beam e1 is irradiated. The secondary electron energy analyzer comprises a collimation unit for forming one or more electrostatic lenses by a nonuniform electrical field distribution and for having an electrostatic lens collimate the trajectory of a secondary electron e2 for its injection into a retarding grids (mesh electrode). The collimation unit comprises at least three cylindrical electrodes positioned between the sample surface and the retarding grid (mesh electrode) and numbered first, second and third from the one closest to the sample surface.