A display device (DA) includes an organic light emitting display panel (DP) and a control module (10). The organic light emitting display panel (DP) includes a first display part (FP) and a second display part (BP) bent from the first display part (FP) with respect to a bending axis (IL) and configured to display a gradation image. The control module (10) is configured to control images displayed in the first and second display parts (FP, BP). At least one of color, brightness, and chroma of the gradation image is varied along a direction perpendicular to the bending axis (IL) of the organic light emitting display panel (DP). A user perceives that an image distortion caused by a shape of the organic light emitting display panel is caused by the gradation image.