Provided are an organic light emitting display device and a method of manufacturing the organic light emitting display device. The method of manufacturing an organic light emitting display device includes forming a sacrificial layer on a lower mother substrate in which a plurality of cells is defined, forming a flexible substrate on the sacrificial layer, forming a display unit including a circuit unit and an organic light emitting diode in each of the plurality of cells on the flexible substrate, removing the lower mother substrate, bonding a supporting film to the flexible substrate, irradiating a portion of the supporting film corresponding to a boundary of a bending area of the flexible substrate, removing a portion of the supporting film corresponding to the bending area of the flexible substrate, performing a process for enhancing adhesion of the supporting film remaining after removing a portion of the supporting film, irradiating a boundary between a non-display area extended from the bending area and a pad area extended from the non-display area, and separating the plurality of cells into cell units by irradiating boundaries of the plurality of cells.