This invention is provided with: a light source; a light scanning mirror; a measurement mechanism for measuring a change in the intensity of light reflected from an eyeball as time elapses through the scanning of at least a surface of the pupil with a light beam by means of the light scanning mirror; a sampling mechanism for sampling the intensity of light reflected from the pupil from the measured change in the intensity of the reflected light as time elapses; and a mechanism for detecting the size and the position of the pupil by synchronizing the sampled intensity of light reflected from the pupil, and the scanning time during which the surface of the eyeball is scanned; and an image generating mechanism for forming an image on the retina of the eyeball by projecting a light beam for generating an image onto the pupil in the detected position while scanning.