A digital camera comprises a CCD for subjecting subject light flux incident from a photographing lens to photoelectric conversion and outputting subject image signals, a movable mirror section, arranged in the imaging light path of the CCD, for reflecting some of the subject light flux and transmitting the remainder, a range finder/photosensor for receiving subject light flux reflected by the movable mirror member and carrying out ranging integration, and an optical system drive mechanism for carrying out focal point adjustment of the photographing lens based on output of the range finder/photosensor. In a sequential shooting mode for sequentially acquiring images using the CCD, during the imaging operation by the CCD ranging integration by the range finder/photosensor 217 is carried out using subject light flux that has been reflected by the movable mirror member.