An ophthalmologic apparatus comprising: a tomographic image acquiring means configured to acquire a tomographic image of an eye; a tilt calculation means configured to calculate a tilt (L1 vs L2) of the tomographic image based on a position of a predetermined layer (RPE, NFL) in the tomographic image; and a relative position changing means configured to change a relative position between the tomographic image acquiring means and the eye based on the calculated tilt of the tomographic image, characterized in that the ophthalmologic apparatus further comprises: an evaluation index calculation unit configured: to calculate a first image evaluation index of a tomographic image acquired by the tomographic image acquiring means before the change of the relative position by the relative position changing means, and to calculate a second evaluation index of a tomographic image acquired by the tomographic image acquiring means after the change of the relative position by the relative position changing means, wherein said first and second image evaluation indices represent an image quality guide of the respective tomographic image; a comparing means configured to compare the first and the second image evaluation indices, wherein the relative position changing means is configured to change the relative position between the tomographic image acquiring means and the eye back to the position before the change of the relative position in a case that the second image evaluation index is smaller than the first image evaluation index. a tomographic image acquiring means configured to acquire a tomographic image of an eye; a tilt calculation means configured to calculate a tilt (L1 vs L2) of the tomographic image based on a position of a predetermined layer (RPE, NFL) in the tomographic image; and a relative position changing means configured to change a relative position between the tomographic image acquiring means and the eye based on the calculated tilt of the tomographic image, characterized in that the ophthalmologic apparatus further comprises: an evaluation index calculation unit configured: to calculate a first image evaluation index of a tomographic image acquired by the tomographic image acquiring means before the change of the relative position by the relative position changing means, and to calculate a second evaluation index of a tomographic image acquired by the tomographic image acquiring means after the change of the relative position by the relative position changing means, wherein said first and second image evaluation indices represent an image quality guide of the respective tomographic image; a comparing means configured to compare the first and the second image evaluation indices, wherein the relative position changing means is configured to change the relative position between the tomographic image acquiring means and the eye back to the position before the change of the relative position in a case that the second image evaluation index is smaller than the first image evaluation index. an evaluation index calculation unit configured: to calculate a first image evaluation index of a tomographic image acquired by the tomographic image acquiring means before the change of the relative position by the relative position changing means, and to calculate a second evaluation index of a tomographic image acquired by the tomographic image acquiring means after the change of the relative position by the relative position changing means, to calculate a first image evaluation index of a tomographic image acquired by the tomographic image acquiring means before the change of the relative position by the relative position changing means, and to calculate a second evaluation index of a tomographic image acquired by the tomographic image acquiring means after the change of the relative position by the relative position changing means, wherein said first and second image evaluation indices represent an image quality guide of the respective tomographic image; a comparing means configured to compare the first and the second image evaluation indices, wherein the relative position changing means is configured to change the relative position between the tomographic image acquiring means and the eye back to the position before the change of the relative position in a case that the second image evaluation index is smaller than the first image evaluation index.