Provided is an elevator door device including: a rail that is disposed above an entrance; an opening and closing part of the entrance; and a locking mechanism that locks the opening and closing part. The locking mechanism includes: an engaging part including an engaging body that changes its position between a releasing position and an engaging position in association with the opening and closing of the opening and closing part; and an engaged part including an engaged body engaged with the engaging body at the engaging position. The engaged part is disposed in an area between the rail and the entrance, and overlaps with the rail as seen in plan view in the area. The opening and closing part has such a shape as to be able to open and close without abutting on the engaged part.