A test apparatus includes a movable stage to support a sample, tips above the stage that have different shapes and alternately perform profiling and milling on the sample, a tip stage connected to a cantilever coupled to the tips, the tip stage to adjust a position of the cantilever, a position sensor to obtain information about a positional relationship between the tips and the sample, a stage controller to control movements of the stage and the tip stage, based on the information about the positional relationship, and a tip controller to select the tips for performing the profiling or milling and to determine conditions for performing milling, wherein a depth of the sample being processed by the milling in the first direction is controlled based on a relationship between a distance between the tips and the sample and a force between the tips and the sample.