In a digital camera, the state of copying is monitored and displayed when image data stored in a main memory are copied to an auxiliary memory, and data for preventing illegal copying are added thereto, in order to improve operability and reliability. When a copying mode is designated, the image data stored in the main memory MM upon photographing are transferred and copied to a detachable auxiliary memory MC by way of a bus B. During copying, the number of uncopied image data in the main memory MM and the number of image data which can be copied to the auxiliary memory MC are sequentially displayed in a liquid crystal display section 30, while each image data is copied with management data indicative of the date and time of copying or the like added thereto. Also, flag data indicating that copying is in progress and that copying has been completed are added thereto. Further, when the auxiliary memory MC is attached to or detached from the camera during copying or photographing, the system is forcibly reset, thereby preventing abnormality from occurring beforehand.