A rail fastening device that is designed to tightly hold a rail on a prestressed-concrete tie by fastening an elastic fastening member bridged between a flange portion of the rail and a stepped portion formed on the tie, by screwing a fastening bolt into a female receptacle buried in the tie. Where the elastic fastening member and the inclined stepped portion of the tie are pressed together, a wedge-like member, which as an inclination conforming to that of the stepped portion, is interposed so as to prevent displacement of the elastic fastening member due to vibration and the like and so as to permit inching adjustment of the installation location of the rail fastening device.