A transparent display device is provided, which includes: a transparent display; a camera; a graphic processor configured to generate an augmented reality (AR) object; and a controller configured to operate in at least one of a transparent AR mode in which the AR object is displayed on the transparent display and a video AR mode in which the AR object is displayed on an image captured by the camera. The controller is further configured to switch between the transparent AR mode and the video AR mode in response to an occurrence of a predetermined event.