An apparatus includes a position detecting unit for detecting the position when a positioning unit completes positioning in a working distance direction, a first acquisition unit for acquiring information about a curvature radius of a cornea of a subjects eye, a second acquisition unit for acquiring information about an intraocular pressure of the subjects eye at a predetermined position in a movable range, which is set in the working distance direction in such a way as not to exceed a proximity limit position relative to the subjects eye, and a control unit for controlling the second acquisition unit based on outputs of the position detecting unit and the first acquisition unit in such a way as to maintain a predetermined distance between the cornea of the subjects eye and the proximity limit position in the working distance direction, regardless of the curvature radius of the cornea of the subjects eye.
