In order to realize to improve safety performance of a filing system by satisfying the minimum requirement of protecting the filing system even if a shooting operation is performed in any condition, management information of a file for a shot image is to be priorly written in a storage medium, and the management information of the filing system is to be updated immediately after performing the shooting operation even if the shooting operation is performed in any condition. Accordingly, even if an unexpected accident such as detaching of a storage medium or extraction of a power supply unit by a user is happened, since the minimum requirement of protecting the filing system is satisfied, it is possible to prevent a state that image data which was already shot can not be accessed.