Charged particle beam device adjustment method and charged particle beam device

A light irradiation position adjustment method for adjusting an irradiation position of first light in a charged particle beam device, the charged particle beam device including:

• a particle beam source configured to irradiate a sample with a charged particle beam;
• a particle beam detector configured to detect a particle beam from the sample and generate a particle beam electric signal;
• a light source configured to generate the first light with which the sample is irradiated;
• a movable mechanism configured to move the irradiation position of the first light;
• a photodetector configured to detect second light emitted from the sample due to the irradiation using the first light and generate a photoelectric signal;
• a sample stage having a configuration allowing the sample to be placed and moved thereon;
• and
• a control device, the method comprising:
• the light source irradiating, with the first light, an adjustment sample placed on the sample stage and including a reference structure;
• the photodetector detecting the second light, that is generated by the first light being modulated by the reference structure, and sending the photoelectric signal to the control device;
• and
• the control device issuing a command to change the irradiation position of the first light so as to pass through the reference structure, and performing an adjustment, based on a change in the photoelectric signal, the movable mechanism such that an irradiation position of the charged particle beam and the irradiation position of the first light match.