The present invention addresses the problem wherein, on a loading space with a hood covering from above the loading space of a freight-train car, guide rails are disposed in a manner which does not interfere with the loading and unloading of cargo or cause deterioration in the working efficiency of a worker, the guide rails being provided so as to support and guide a hood frame, the hood frame supporting the hood and being installed so as to be movable in the longitudinal direction. To address the above-described problem, provided is a guide rail-attached structure for a loading space with a hood, the guide rail-attached structure having stepped portions (10) lower than the floor surface of the loading space on either side in the vehicle width direction of the loading space of a freight-train car. A pair of parallel guide rails (11), which supports rollers (25) provided at the lower end of a hood frame (3) and guides the longitudinal movement of the rollers (25), are mounted to the stepped portions (10). At l
