Abstract: An operation input device according to one embodiment includes: a display device that emits light to display information; an aerial image forming device that reflects the light from the display device a plurality of times to display a display plane with a switch in an air as a virtual image; a sensor that detects a position of a target object approaching the switch; and a determination unit that determines whether or not the switch has been operated, based on the position of the target object detected by the sensor. An eyepoint position where eyes of an operator that operates the switch are located is set in advance. The aerial image forming device is disposed on a straight line connecting the eyepoint position and the display plane.