Anti-thermal deformation device of double fire doors

The present invention relates to a dual fire door, and more particularly, to a device for preventing deformation of a dual fire door that prevents hinge detachment by minimizing expansion and deformation of the dual fire door by heat during a fire and prevents flames or smoke from spreading. To solve the technical problem, according to the present invention, provided is a device for preventing deformation of a dual fire door, in which right and left doors are rotated at 180 degrees to both sides. The device includes: a hinge shaft installed at both ends of the dual fire door; a rotary member connected to the hinge shaft inwardly and having a hinge embedded in the dual fire door to allow the dual fire door to be rotated with respect to the hinge shaft; a frame member provided on a rear surface of the hinge shaft and having a fixed bending portion, one side of which is embedded in a wall and an opposite side of which is formed with a bent groove, the frame member extending in a longitudinal direction; and a stopper member installed on a rear surface of the dual fire door, and having a protrusion protruding from one side thereof, wherein the protrusion is inserted into the fixed bending portion to prevent the hinge from being detached due to the deformation of the dual fire door when a fire occurs.