Provided is a display apparatus including an image forming device configured to form an image, an optical system configured to provide an output image by combining light containing an outside landscape with the image formed by the image forming device, and a driving device configured to adjust a distance between the image forming device and the optical system, wherein the driving device includes a fixed frame, a movable frame which faces the fixed frame and is movable, an actuator configured to change a distance between the fixed frame and the movable frame, and a fixing member configured to fix the distance between the fixed frame and the movable frame, wherein the image forming device is fixed to the movable frame.