PARALLAX DETECTING APPARATUS, IMAGE CAPTURING APPARATUS, PARALLAX DETECTING METHOD, AND STORAGE MEDIUM

There is provided a parallax detecting apparatus. A first obtainment unit obtains a first viewpoint image and a second viewpoint image that have different viewpoints from each other in a first direction. A second obtainment unit obtains displacement information that specifies a displacement amount in a second direction between positions in the first viewpoint image and the second viewpoint image corresponding to a same position in a shooting range. The displacement amount varies in conformity with a parallax amount between the positions. The second direction is perpendicular to the first direction. A calculation unit performs correlation calculation processing with respect to each of a plurality of reference regions corresponding to a plurality of reference positions in the second viewpoint image. A detection unit detects a parallax amount at a base position in the first viewpoint image based on calculated correlations.