PURPOSE: To provide a light beam scanner which stabilizes scanning beams without fetching external disturbance and to greatly improve picture quality.

CONSTITUTION: A hologram scanner is provided with a laser diode which emits a divergence light, a semiconductor laser 10 which has a photodiode monitoring the optical output, a collimator lens 11 which converts the divergence light from the laser diode to parallel light, a preset prehologram 20 and a hologram disk 30 which deflection scans the parallel rays of light that are made incident through the preset hologram 20. The arrangement relationship between the prehologram 20 and the collimator lens 11 is deviated from the Bragg condition so that the reflected light from the hologram disk 30 does not return to the laser diode and the photodiode.