A manufacturing method of an organic light emitting diode (OLED) display includes: supplying a circuit film on the pad area of the display panel and bonding a first end portion of the circuit film to the pad area; vertically standing and inserting the display panel in a bonding device; holding a portion of the circuit film including a second end portion to be horizontal by using a rotating device including a vacuum absorbing portion; supplying a flexible printed circuit (FPC) into a space under the second end portion of the circuit film, and attaching the flexible printed circuit to the second end portion of the circuit film; and operating the rotating device to move the second end portion to a vertical position, and separating the circuit film from the vacuum absorbing portion.