Method of adjusting ion beam device and the emitter tip

An object of the present invention, even when lowering the cooling temperature in order to observe the specimen at a higher signal / noise ratio, the ion beam apparatus nanopyramid can be formed with a single atom stably to the tip of the emitter tip it is to provide. In the present invention, in an ion beam device to observe or processing of the sample by irradiating an ion beam generated from a gas field ion source to a sample, when forming the nano pyramid having one atom to the tip of the emitter tip set, while maintaining the temperature of the emitter tip to a second temperature lower than the high and room temperature than the first temperature for generating an ion beam, a second voltage higher than the first voltage when the extraction voltage is generated an ion beam to, to field evaporation of atoms of the emitter tip tip.