A display device includes an image generation device configured to superimpose an image on a landscape and allow a viewer to visually recognize the image, a control device configured to control the image generation device, and an operation unit configured to receive an operation related to display of the image. The image generation device generates a first image constantly displayed and a second image displayed on the basis of occurrence of a predetermined event, and the control device changes a display mode of one or both of the first image and the second image output by the image generation device on the basis of a content of the image generated by the image generation device and an operation content by the operation unit.