In a method for manufacturing a display device, the method includes: providing a display panel divided into a cutting area and a body part surrounding the cutting area; attaching a dummy film on a bottom surface of the display panel; cutting the cutting area by irradiating laser light toward a cutting line defined as a boundary between the cutting area and the body part; irradiating the laser light to a groove line of the dummy film, which overlaps the cutting line, to define a groove in the dummy film along the groove line; and separating the dummy film from the body part.