A double-sided organic light-emitting display device includes: a first electrode layer for emitting electrons; a second electrode layer which emits holes and is disposed perpendicularly to the first electrode layer; an organic light-emitting layer interposed between the first electrode layer and the second electrode layer, and including multiple pixels so as to emit light at a portion where the first electrode layer and the second electrode layer intersect with each other, by the collision between the electrons and the holes; and a reflector unit formed in an arbitrary pattern which reflects, in the opposite direction, light transmitted through the first or the second electrode layer, or a pattern reversed with respect to the arbitrary pattern, such that the multiple pixels display a first image on one surface in the arbitrary pattern, and display a second image on the other surface in the pattern reversed with respect to the arbitrary pattern.