1. An image information registration system comprising: an image information acquisition unit that acquires image information appearing on a surface of a medium by optically reading the surface of the medium; a rotation angle information acquisition unit that acquires rotation angle information corresponding to a rotation angle of the medium with respect to a reading direction of the image information acquisition unit based on the image information; a retrieval information acquisition unit that acquires retrieval information including at least one item of attribute information and association system information that represents an association system which are correlated with the rotation angle information based on the acquired rotation angle information; a target information acquisition unit that acquires one or a plurality of items of target information stored in the association system identified by the association system information according to the acquired retrieval information; and an image information registration unit that registers the image information according to the acquired one or plurality of items of target information.