An apparatus is disclosed which projects light onto a retina of a viewer, to thereby allow the viewer to perceive a display object via a virtual image. The apparatus includes: an emitter emitting light; a modulator modulating the light; a display unit outputting the modulated light to the retina of the viewer through an exit of the display unit, to thereby display in an image display region an image representative of the display object in the form of a virtual image; and a controller controlling the emitter and the modulator so that the image is displayed in the image display region. The controller detects a relative motion of the viewer with respect to a position of the viewer, and performs at least one of control of a display/non-display status of the image, and control of a display position of the image, in accordance with the detected relative motion.