To effectively suppress a swing of a door in plate thickness direction.

A slide door comprises a door 11 and a door sill 12 located on the lower side of the door 11 and installed along the width direction of the door 11. On the lower end of the door 11, a bracket 16 to support a rotating roller 15 as a rolling element is installed whereas, on the door sill 12, a recessed groove 31 capable of receiving the rotating roller 15 is formed along its extending direction. In an assembled condition where the rotating roller 15 is received by the groove 31, the outer peripheral surface 15A of the rotating roller 15 is brought in contact with the inner surface 31A of the groove 31 and, when the door 11 is moved, the outer peripheral surface 15a can be rotated while it is brought in contact with the inner surface 31A.