An apparatus has a feature value extracting section 106 for extracting a feature value from a search key image; a distance calculating section 107 for calculating distances between the feature values of search target images and the feature value of the search key image; a distance analyzing section 108 for analyzing the distances calculated by the distance calculating section 107, and for selecting a feature value having a feature similar to the search key image as a feature value effective for the image search; and a search executing section 109 for arranging the search target images in a feature value space with coordinate axes to which a principal component analysis result of the feature value effective for the image search is assigned, and for searching for an image similar to the search key image from within the feature value space.