It is an object to provide an image sensing apparatus which can shorten the time required for the creation of correction data by reducing the amount of data used for the creation of correction data. In order to achieve the above object, an image sensing apparatus according to this invention includes a plurality of pixels, a first calculating unit which creates correction data by performing computation using signals which are acquired by image sensing in an unexposed state and smaller in number than said plurality of pixels, and a second calculating unit which corrects image data of the plurality of pixels, acquired by image sensing in an exposed state, by using the correction data.