Upon the activation of a system, an activation program that at the least is required for activating an image pickup unit is fetched to a buffer memory and is executed to enable photographing. Thus, when a release button is manipulated, image data obtained by the image pickup unit is stored in the buffer memory, and thereafter the remaining activation programs, including a program for obtaining information associated with a memory card, are fetched to the buffer memory and are executed. Since, prior to other processes such as the acquisition of information associated with the memory card, only the process for activating the image pickup unit is performed to quickly activate the system and enable photographing, the time required for activation from when power is switched on until photographing is enabled is shortened, and the probability that a photo opportunity will be lost is reduced considerably.