An image sensing apparatus comprises an image sensor configured to convert an optical image of a subject into image signals by photoelectric conversion. The image sensing apparatus acquires information for estimating a magnitude of a dark current in the image sensor, and, on the basis of the acquired information, selects any one of vertical linear noise correction processing, black subtraction processing, and normal readout processing in which neither the vertical linear noise correction processing or the black subtraction processing is carried out. Then, the image sensing apparatus carries out the vertical linear noise correction processing to correct a vertical linear noise in an image if the vertical linear noise correction processing is selected, or the black subtraction processing to correct a vertical linear noise and a fixed pattern noise in an image if the black subtraction processing is selected.