1. A digital pictorial book system for searching for and providing a user with an explanation of an object captured by an image capturing module comprising: an image capturing module for capturing an image; a main object selecting module for selecting a main object out of the image; a feature extracting module for extracting a feature of the main object; an explanation searching module for searching for the explanation of the main object in a plurality of image databases, which store explanations of the objects corresponded to a plurality of different kinds of features of the subjects by using the feature extracted by said feature extracting module; and a distinguishing feature selecting module for selecting a distinguishing feature, of which an overlap of certainty distributions is the smallest for each object and each kind of the feature out of the different kinds of features stored in the image database corresponded to the plurality of objects in case the explanations of the plurality of objects are searched out by said explanation searching module.