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 mechanism (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 mechanism (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 mechanism (40) that performs marking with the three-dimensional coordinates as a laser beam focal point.