This invention is to shorten the time of white balance processing. In order to achieve this object, this invention provides an image sensing apparatus including an image sensing section which senses an object image and scans charge of pixels by interlaced-scanning to acquire image data of one frame by two fields, a memory which temporarily sequentially stores the image data output from the image sensing section, and a control section which reads out the image data in a first field and that in a second field from the memory and calculates a white balance coefficient before the image data in the second field is completely read from the image sensing section.