1. An image search device, comprising: a query feature amount obtaining unit means for obtaining a plurality of query feature amounts, each of said plurality of query feature amounts indicating a local feature of an image serving as a query; an image feature amount selector for selecting, for each of the plurality of query feature amounts, image feature amounts from a plurality of image feature amounts respectively indicating local features of each image to be searched, which are stored in a storage unit in advance for each of the images; a score generating unit for generating a score indicating a degree of similarity between each of the plurality of images to be searched and the image serving as the query based on the image feature amounts selected relative to the plurality of query feature amounts; and an image selector for selecting at least one image from the plurality of images to be searched based on the score generated for the image, wherein the image feature amount selector selects, for each of the plurality of query feature amounts, not more than one image feature amount per the image to be searched from a plurality of image feature amounts which are not selected relative to a query feature amount which is different from the corresponding one of the plurality of the query feature amounts.