This invention makes shot image data match dust correction data as much as possible even when the dust adhesion state changes. An image capturing apparatus includes an image capturing unit which photo-electrically converts, by an image sensor, an object image formed by a photographing lens to generate an image signal, a foreign substance information detection unit which detects, based on the image signal, foreign substance information serving as information on at least the position of a foreign substance adhering to an optical element placed in front of the image sensor, and an association unit which associates an image signal with foreign substance information, and associates foreign substance information detected by the foreign substance information detection unit not only with an image signal obtained after detecting the foreign substance information, but also with even an image signal obtained before detecting the foreign substance information.