The invention provides an image processing apparatus comprising: an acquisition unit configured to acquire a plurality of captured images captured by an image capturing apparatus; a determination unit configured to determine position information of the image capturing apparatus for each of the plurality of captured images so that an evaluation value becomes smaller; and a connecting unit configured to connect the plurality of captured images projected onto a reconstruction plane using the determined position information of the image capturing apparatus, wherein the determination unit comprises a calculation unit configured to project each of the plurality of captured images onto the reconstruction plane based on the set position information and to calculate, as the evaluation value, an image difference between the projected images in a overlapping region between the projected images.