A neutral particle beam processing apparatus comprises a workpiece holder (20) for holding a workpiece (X), a plasma generator for generating a plasma in a vacuum chamber (3), an orifice electrode (5) disposed between the workpiece holder (20) and the plasma generator, and a grid electrode (4) disposed upstream of the orifice electrode (5) in the vacuum chamber (3). The orifice electrode (5) has orifices (5a) defined therein. The neutral particle beam processing apparatus further comprises a voltage applying unit for applying a voltage between the orifice electrode (5) and the grid electrode (4) via a dielectric (5b) to extract positive ions from the plasma generated by the plasma generator and pass the extracted positive ions through the orifices (5a) in the orifice electrode (5).
