1. An image sensing apparatus capable of sensing moving image and still image, comprising: a detecting unit adapted to detect an instruction for sensing still image during sensing moving image; a first storing unit adapted to store still image data which has higher density than moving image data and corresponds to a frame of sensing moving image; a processing unit adapted to process the stored still image data by dividing the stored still image data into a number of image areas and processing still image data in each image area within interval time other than moving image data processing time.