1. A database production method, comprising: a representative image selection step of selecting certain images each as a representative image which represents an image content from the image content; a display processing step of causing a display apparatus to display the representative image; an operation inputting step of allowing a user to input image text information corresponding to the representative image; and a database production step of registering representative characteristic information extracted from the representative image in accordance with a predetermined extraction method and the image text information inputted at the operation inputting step in an associated relationship with each other to produce a database for acquiring, using arbitrary image characteristic information for each image extracted from an arbitrary image content in accordance with the extraction method, substance character information corresponding to an image which the arbitrary image content has.