Abstract: A disclosed visitor information system includes a processor programmed to execute a process including registering, as group information for groups of visitors, group identification information of a group, and medium identification information of authentication media owned by respective visitors, and registering, upon authentication being normally performed by the login operation using the authentication medium, identification information or locational information of an apparatus via which a first visitor has performed a login operation in visitor information corresponding to the group information based on the medium identification information; and acquiring, upon authentication being normally performed by the login operation using the authentication medium, locational information of a second visitor belonging to the same group as the first visitor from the group information, based on the medium identification information and the group identification information to provide the first visitor with information in