An input device includes a display unit that displays an aerial image, and a detection unit that detects a user operation related to the aerial image. The display unit includes a light guide plate disposed between a half mirror and a retroreflective plate and a light source irradiating the light guide plate. The display unit displays the aerial image of a light diffusion surface formed on the light guide plate in response to incident light. When the user operation related to the aerial image is detected, the display unit turns off the light source to notify a user of input confirmation.