1. An image recognition method for identifying, when an image representing an object is provided as an input image, an image including the object from an image database through retrieval of local descriptors, the image recognition method comprising the steps of: extracting a plurality of local descriptors indicative of local features of the input image; limiting local descriptors obtained from images in the image database down to target local descriptors to be retrieved from each of the plurality of local descriptors in the input image; retrieving from the target local descriptors such local descriptors, each of the retrieved local descriptors being similar to each of the local descriptors in the input image so as to specify the retrieved local descriptors as neighbor local descriptors respectively corresponding to the plurality of local descriptors in the input image; and identifying at least one image to be a recognition result (recognition-result-image), from among images which include the specified neighbor local descriptors, through a statistical process, wherein: the limiting step limits the number of the target local descriptors to the number such that the recognition-result-image is identifiable; and each of the steps is executed by computer.