1. An image searching method, comprising: (a) obtaining, by an image search apparatus, features of an input image; (b) obtaining, by the image search apparatus, words to which the respective features correspond, and adjacent words that are adjacent to the respective words to which the features correspond, wherein when a first word cell of a plurality of word cells that are included in a visual feature space is assigned to a word, an adjacent word is a word assigned to at least one second word cell of the plurality of word cells, the second word cell being adjacent to the first word cell to which the word is assigned, wherein the plurality of word cells is assigned to different words, and at least one word being within a predetermined distance from the word is designated as the adjacent word; (c) searching for, by the image search apparatus, an image that is identical or similar to the input image based on information associated with a first group of images corresponding to the word and information associated with a second group of images corresponding to the adjacent word, the information on the first and second groups of images being stored in a database.