A corneal surgery apparatus which comprises a laser irradiation optical system and an eye position change detection unit comprising an illumination optical system and an image pick-up camera picking up an anterior-segment image of a patient's eye and detecting the change in eye position based on an iris pattern in the image, and is arranged such that an irradiation position tracks movement of the eye to ablate a cornea, wherein the apparatus further comprises a contrast adjustment unit extracting a pupil portion and an iris portion based on luminance information of the image, and increasing/decreasing a set value of an illumination light amount and/or a set value of a gain of the camera to increase a contrast of the pupil portion to the iris portion and/or a contrast of the iris pattern within a range that luminance at the iris portion is not saturated.