Abstract: It is judged whether a marking unit formed on a material becomes a bright mark or a dark mark. Based on this judgment, for the work W of a material in which the marking unit becomes a bright mark, the code symbol of the 2-dimensional code of the original image is bright/dark-reversed to generate a reversed code symbol 1R. By doing this, a laser marker 10 is controlled so as to apply a laser beam to the cell of the background portion without applying the laser beam on the cell of the code portion. On the other hand, in the case of the normal material in which the marking unit becomes a dark mark, the laser marker 10 is controlled to apply the laser beam to the cell of the code portion without applying the beam to the cell of the background portion.

Abstract: The present invention relates to a laser marking device that irradiates a laser beam on a workpiece (W) to transform a portion inside the workpiece at a focal point of the laser beam, thus putting a dot in each predetermined area. The laser marking device includes acquiring means (10, 20) that acquires, as information on the dot, at least two-dimensional position information of an exposed section of the workpiece (W), and density information of the dot, coordinate setting means (30) that calculates, for each dot according to the density information, dot depth information showing the distance from the surface of the workpiece (W) to the dot in the thickness direction of the workpiece (W), and sets three-dimensional coordinates for each dot based on a position specified by the dot depth information and the two-dimensional position information, and laser marking means (40) that performs marking with the three-dimensional coordinates as a laser beam focal point.