In an ophthalmologic apparatus, the coordinates of three illuminated spots
on a cornea-reflected image calculated from a front eye part image picked
up by a two-dimension image pickup element and a pupil diameter are
calculated, and the position of the centroid of the pupil is calculated
from the front eye part image. When the pupil diameter is smaller than a
predetermined value, alignment is effected from the shift from the center
of the pupil, and when the pupil diameter is larger than the
predetermined value, alignment is effected on the basis of the shift
amounts from the illuminated spots on the cornea-reflected image. Also, a
controlling method is changed over by the difference between the
positions of the illuminated spots on the cornea-reflected image and the
position of the centroid of the pupil. Also, the tolerance level of
alignment is varied by the size of the pupil diameter.