The ophthalmologic apparatus comprises an optical system for acquiring data of a subject's eye optically, an image acquiring unit that acquires a first image of an anterior segment of the subject's eye and a second image of the anterior segment at different timings from each other, a rotational movement amount calculator that calculates a rotational movement amount between a partial image in the second image and a corresponding partial image in the first image, the corresponding partial image corresponding to the partial image, a registration unit that performs registration between the corresponding partial image and the partial image in a rotation direction based on the rotational movement amount, a parallel movement amount calculator that performs a phase only correlation processing on the corresponding partial image and the partial image registered by the registration unit to calculate a parallel movement amount between the corresponding partial image and the partial image, a movement mechanism that moves the subject's eye and the optical system relative to each other, and a controller that controls the movement mechanism based on at least one of the rotational movement amount and the parallel movement amount.
