A charged-particle beam apparatus is provided with a cathode to emit charged particle beams, an anode to propagate the charged particle beams emitted from the cathode in a sample surface direction, an aperture to propagate a charged particle beam passing through an opening at a predetermined position and of a predetermined shape, among the charged particle beams passing through the anode, in the sample surface direction, and a first electrode that is disposed between the anode and the aperture, and is set at a first electric potential of a polarity repelling a polarity of an ion generated due to collision of a charged particle beam.