A motorcycle having a loading space for stably loading luggage. Luggage may be loaded onto a rear loading space with the luggage being fixed by fastening a rope to a grab rail. A seat back is provided that also functions as a passenger seat. When only one person rides, luggage can be loaded onto the rear space and can be fastened by hanging the luggage on a hook directly or indirectly using the rope. As the hook disappears when a seat back that also functions as a passenger seat is positioned to be substantially horizontal, the appearance quality is not damaged. Therefore, luggage can be stably loaded and a larger quantity of luggage can be carried by the motorcycle. Left and right slider are provided for permitting free longitudinal movement of the seat from a substantially horizontal position to a raised position.