1. A registering metadata apparatus comprising: a first acquisition unit which acquires a first image, first metadata, and a first position within the first image, the first position being for displaying the first metadata; an extraction unit which extracts local features from the first image; a calculation unit which searches for a group of the local features within a predetermined distance from the first position, and calculates a representative point of the group, the representative point being a center of gravity position of the group of the local features; a search unit which matches the first image with a plurality of images stored in a database by using the local features, and searches for a second image which coincides with the local features; and a registration unit which calculates at least one second position, within the second image, corresponding to the representative point, and registers the second position and the first metadata as metadata for the second image.