Door guide apparatus preventing breakaway of a elevator door and locking apparatus involving this

A door guide and a locking apparatus including the same are provided to prevent a door from being separated by external impacts when the door is closed, by firmly maintaining its state constrained by a doorsill, thereby protecting passengers in the elevator from falling. A locking device for preventing breakaway of an elevator door comprises a door guide unit(100) and a door guide hanging unit(200). The door guide unit comprises a door fixing frame(110), a door shoe(120), and an engagement part(130). The door fixing frame, made of stiffened materials, is secured on a lower side of a door panel(10). The door show, assembled to the lower side of the door fixing frame, guides the door along a groove of a doorsill(30). The engagement part maintains the connection with the door guide hanging unit to prevent its separation from the doorsill. The door guide hanging unit comprises a doorsill fixing frame(210) and a counter-engagement part(230). The doorsill fixing frame is secured on the doorsill. The counter-engagement part having a corresponding shape of the engagement part, makes connection with the door guide unit to prevent separation of the door guide unit from the doorsill.