1. An image sensing apparatus which has a camera shake correction function of performing a camera shake correction on a plurality of images sensed by an image sensing unit by extracting a partial image from each of the sensed images on the basis of correlation between the sensed images, comprising: a camera shake amount detection unit that detects a camera shake amount of said image sensing apparatus, an exposure control unit that controls to expose said image sensing unit for a first exposure time period when the camera shake amount is equal to or less than a predetermined amount, and for a second exposure time period which is shorter than the first exposure time period when the camera shake amount is greater than the predetermined amount; and an addition unit that, when the camera shake amount is greater than the predetermined amount, adds image signals of a plurality of images which undergo the camera shake correction, and outputs the added image signals as one image.