PURPOSE: To easily aim a mark with the beam of a laser diode, to exactly position the mark for a laser scanner before scanning, and to exactly trace the mark by the laser scanner during scanning.

CONSTITUTION: A laser for generating an incident light beam is provided in a head 10 for aiming a mark by a hand scanning head 10, and an optical element such as a positive lens for directing the incident laser beam along a first optical path to the reference plane of a plane perpendicular to an incident laser beam transmitting direction 104 is provided in the head 10 (which is provided also in a blocking wall part 58). The laser light reflected from a mark is going along a second optical path going away from the mark to the head 10. A reflection surface such as a scanning mirror 66 is vibrated back and force, and the mark is scanned. The head 10 is provided with a sensor means 80 for generating an electric analog signal indicating the optical intensity of the reflected laser light, and signal processing means 81-83 which process an electric signal, and process the data of an scanned mark into a digital electric signal.