In a tomographic image photographing apparatus, a deformation of a volume image is corrected accurately even if an object to be inspected moves when the volume image is acquired. An image processing apparatus acquires a tomographic image of the object to be inspected from combined light beams of return light beams, which is obtained by irradiating the object to be inspected with a plurality of measuring light beams, and corresponding reference light beams. In the image processing apparatus, a photographing unit obtains a tomographic image of a fundus with the plurality of measuring light beams, and a detection unit detects a retina layer from the tomographic image. Based on the detected retina layer, a fundus shape is estimated. Based on the estimated fundus shape, a positional deviation between tomographic images is corrected.
