A rail structure for doors comprises a track rail body (3) which supports the door wheels (4) which are attached to a door (6) and freely roll on the track rail body (3), a load support member (2) which is extended along the track rail body (3) and supports the track rail body (3) from the bottom side, a cushion member (7) which is disposed between the track rail body (3) and the load support member (2) and absorbs the vibration from the track rail body (3). A convexo-concave fitting part (8) which performs convexo-concave fitting is formed on the bottom surface of the track rail body (3) and on the upper surface of the load support member (2) via the cushion member (7). Purposes of the invention are to prevent vibrations caused by the running of the door wheels (4) from being transmitted to building, and to improve the efficiency of replacement operations for the track rail body (3), and to lower the cost.