1. An image search device, comprising: a processor; and a memory device that stores a plurality of instructions, which when executed by the processor, causes the processor to: obtain a plurality of query image feature vectors, wherein each of said plurality of query image feature vectors indicate a local feature of a query image; select, for each of the plurality of query image feature vectors, search image feature vectors which indicate local features of each of a plurality of search images, and wherein said search image feature vectors are stored in a storage unit in advance for each of the plurality of search images; generate a score indicating a degree of similarity between each of the plurality of search images and the query image based on the search image feature vectors selected relative to the plurality of query image feature vectors; and select an image from the plurality of search images based on the score generated for the search image, wherein in the selection of the search image feature vectors, an already-selected image list is initialized for each of the query image feature vectors, one or more search image feature vectors are selected for the query image feature vectors, not more than one search image feature vector is selected from the one or more selected search image feature vectors, the not more than one selected search image feature vector has not been extracted from an image included in the already-selected image list, and the image from which the not more than one selected search image feature vector has been extracted is added to the already-selected image list.