1. An image processing apparatus for supporting imaging diagnosis of an eye, the image processing apparatus comprising: an acquisition unit configured to acquire a tomographic image of an examined eye; a detection unit configured to detect a layer boundary of a retina region from the acquired tomographic image; a determination unit configured to determine a position where the detected layer boundary intersects with an upper limit position or a lower limit position of the image in a depth direction of layers as a dividing position of the tomographic image; a dividing unit configured to divide the tomographic image at the dividing position determined by the determination unit based on scan lines in the depth direction of the layers; and a judgment unit configured to judge, for each region divided by the dividing unit, whether the detection by the detection unit is a false detection, wherein the judgment unit calculates, for each of the divided regions, an average density value of the image outside the retina region according to a detection result of the detection unit and judges that the detection in the divided region by the detection unit is a false detection if the average density value is equal to or greater than a predetermined threshold.