A short-time exposure image data and a long-time exposure image data of the same object to be photographed are stored to SE memory and LE memory and then transferred to CPU, motion thereof being detected at a motion detecting section on the basis of the two image data; if no motion is detected, a wide dynamic range, synthesized image as synthesized at a synthesizing circuit on the basis of image data read out from the two memories and compressed is outputted through a selector controlled by CPU. If a motion is detected, the long-time exposure image data read out from the LE memory and processed at a signal processing circuit is outputted through the selector. An image pickup apparatus having a function for generating wide dynamic range, synthesized image by synthesizing image signals corresponding to a plurality of frames of different exposure amounts is thereby able to perform ON/OFF switching of the generating function of synthesized image on the basis of previously taken image data, so that a failed synthesized image can be prevented from being outputted.