An image sensing apparatus according to the present invention includes: an image sensing unit configured to sense an object image and output image signals; a shift amount detecting unit configured to detect a shift amount between two image signals, from the image signals that are sequentially output by the image sensing unit; an image signal synthesizing unit configured to sequentially synthesize the image signals based on detection results of the shift amount detecting unit, and generate a synthesized image signal that has been corrected by the shift amount; and a memory unit configured to accumulate the synthesized image signal, wherein the image signal synthesizing unit performs level adjustment of a signal level, the level adjustment varying for each area of the two image signals that are to be synthesized, and generates the synthesized image signal.