Ion Milling Device

There is provided an ion milling apparatus that can enhance reproducibility of ion distribution.The ion milling apparatus includes an ion source 101, a sample stage 102 on which a sample processed by radiating a non-convergent ion beam from the ion source 101 is placed, a drive unit 107 that moves a measurement member holding section 106 holding an ion beam current measurement member 105 along a track located between the ion source and the sample stage, and an electrode 112 that is disposed near the track, in which a predetermined positive voltage is applied to the electrode 112, the ion beam current measurement member 105 is moved within a radiation range of the ion beam by the drive unit 107, in a state in which the ion beam is output from the ion source 101 under a first radiation condition, and an ion beam current that flows when the ion beam is radiated to the ion beam current measurement member 105 is measured.