In a fuel-cell two-wheeled vehicle, a cooling liquid pouring pipe extending from a pipe line of a cooling system to a cooling liquid supply port member is provided in a winding path so as to pass both side portions, a front portion, and a left rear portion of an axis of a head pipe. The cooling liquid supply port member is located on a central axis of width of the vehicle in the vicinity behind the head pipe. A hydrogen sensor for sensing hydrogen gas in the cooling liquid pouring pipe is mounted on an inside surface of a cap for closing an opening. The cap is removably provided.