An ophthalmologic apparatus according to the embodiments includes an OCT optical system, an alignment unit, an image forming unit, a first calculator, and a second calculator. The OCT optical system is configured to acquire OCT data of a fundus of a subject's eye by projecting measurement light onto the fundus. The alignment unit is configured to perform alignment of the OCT optical system with reference to a predetermined site of the subject's eye. The image forming unit is configured to form a tomographic image of the fundus based on the OCT data acquired by the OCT optical system which has been aligned by the alignment unit. The first calculator is configured to calculate a first tilt angle of the tomographic image. The second calculator is configured to calculate a second tilt angle of the fundus by correcting the first tilt angle based on alignment result of the OCT optical system with respect to the predetermined site by the alignment unit.