To provide an owner identification system for a bicycle or a motorcycle left intact, which is easy to find the owner of the specific bicycle in particular, can contribute to countermeasures against leaving intact or a theft, and has a new structure, and to provide a registration card and a marker having a new structure for it.

This owner identification system is provided with an owner data establishment means and an owner data management means. The specific bicycle information and/or owner information can be efficiently registered and managed by mechanically and electronically registering the marked information of the registration card. A person having a specific right directly inputs the information on the marker fitted to the specific bicycle to a terminal unit or mechanically inputs it with a reader, gains access to a prescribed storage medium with a communication means, and specifies the specific bicycle and/or the bicycle owner to quickly find the owner of the specific bicycle in this owner identification system for the bicycle or the motorcycle.