Abstract: A collapsible double door assembly includes a number of serially connected panels each provided with a pair of inwardly and outwardly deviated pivotal suspension rollers, a horizontal guide rail constituted by an inner rail member and an outer rail member arranged in parallel in close proximity for separately guiding the suspension rollers, and one or two door storage areas extending perpendicularly from the guide rail at one or both ends thereof and formed by separating and independently bending the two rail members with different radiuses of curvature each defining an arc of a quarter of a circle. The radius of curvature of the outer rail member is relatively greater than that of the inner rail member. The distance between the two rail members in a door storage area is slightly smaller than the distance between the two suspension rollers of a panel.