Ion Milling Device

Provided is an ion milling device capable of improving the reproducibility of an ion distribution. An ion milling device includes: an ion source (1); a sample stage (2) on which a sample (4) to be processed by being irradiated with an unfocused ion beam from the ion source (1) is placed; and a drive unit (8) configured to be arranged between the ion source (1) and the sample stage (2), and to move a linear ion beam measuring member (7) extending in a first direction to a second direction orthogonal to the first direction, in which the drive unit (8) moves the ion beam measuring member (7) within an emission range of the ion beam in a state where the ion beam is outputted from the ion source (1) under a first emission condition, and an ion beam current flowing through the ion beam measuring member (7) is measured by irradiating the ion beam measuring member (7) with the ion beam.