In a disclosed optical scanner, an optical axis adjustment is made by moving a circuit board on which a light emitting device open-type semiconductor laser is mounted along a base face of an optical box. For a high-quality optical scanning, the circuit board is attached to the base face of the optical box. The invention provides a light emitting element open-type in which a semiconductor laser is disposed in an optical box which is almost hermetically sealed with a cover to avoid adhesion of dusts, electrostatic destroy, and deterioration in picture quality.