An image pickup apparatus comprising a CCD (12), responsive to a periodically occurring driving timing signal, for picking up an image of an object, a shutter key (23) for producing an operation signal when depressed, a main CPU (20) for controlling the whole image pickup operation of the image pickup apparatus, for directly receiving the operation signal produced by operating the shutter key (23), and for sensing as an interrupt signal an initial change in the operation signal to thereby give an instruction to cause the image pickup element to start to pick up the image of the object, and animage processing engine (13), responsive to the instruction given by the main CPU (20), for immediately producing a drive timing signal to cause the CCD (12) to start to pick up the image of the object without waiting for an occurrence of a periodically occurring drive timing signal, and for processing data on the image of the object picked up by the CCD (12).