A rear hub has a hub shaft and a hub outer that is configured to be mounted in a freely rotatable manner to the hub shaft. The hub outer has an outer main body and an adapter. The outer main body is arranged on the radially inward side of a sprocket, and has a first rotation preventing section that engages with an engaging section 64 of the sprocket in such a manner that the outer main body cannot rotate relative to the sprocket. The adapter is mounted in a freely rotatable manner on an adapter mounting section of the outer main body. The adapter includes a second rotation preventing section that engages with the engaging section of the sprocket in such a manner that the adapter cannot rotate relative to the sprocket.