Ion milling device

An ion milling apparatus comprising:

• an ion source;
• a sample stage on which a sample processed by radiating a non-convergent ion beam from the ion source is placed;
• a measurement member holding section that holds a linear ion beam current measurement member extending in a first direction;
• a drive unit that moves the measurement member holding section holding the ion beam current measurement member along a track extending in a second direction orthogonal to the first direction and located between the ion source and the sample stage;
• an electrode that is disposed near the track;
• and
• a controller, wherein
• the controller applies a predetermined positive voltage to the electrode, moves the ion beam current measurement member within a radiation range of the ion beam by the driving unit in a state in which the ion beam is output from the ion source under a first radiation condition, and measures an ion beam current flowing through the ion beam current measurement member when the ion beam is radiated to the ion beam current measurement member.