An electron beam apparatus having a longer life time of cathode, and allowing a plurality of electron beams to be arranged adequately around an optical axis and five or more electron beams to be formed from a single electron gun. The electron beams emitted from a cathode made of ZrO/W (tungsten zirconium oxide) or a cathode made of carbide of transition metal to the off-optical axis directions may be converged on a sample to scan it. The apparatus includes a plate for reducing a vacuum conductance defined between the electron gun chamber side and the sample side, and apertures are formed through the plate at locations offset from the optical axis allowing for the passage of the electron beams. In order to evaluate a pattern on the sample, the electron beam emitted from the electron gun is incident to the sample surface via an objective lens. The objective lens is composed of a flat electrode having an aperture centered on the optical axis and placed in parallel with the sample surface and an electromagnetic lens including a gap formed in a side facing to the sample. Further, in order to inspect a mask, spacing among a plurality of electron beams after having passed through the mask are extended by a magnifying lens and thus widely spaced electron beams are then converted into optical signal in a scintillator.