A control device controls a laser irradiation device to record visible information on a medium by irradiation of a laser beam. The control device includes a drawing information storage unit which stores drawing information of line segments contained in line images of characters, numbers, and symbols. A drawing information acquiring unit acquires drawing information of a line image as an object to be drawn. A thickness information acquiring unit acquires thickness information which specifies a thickness of each line segment. An overlapping line segment detecting unit detects a pair of line segments drawing ranges of which, inclusive of the line segment thickness, overlap each other, based on the thickness information and the drawing information. A line dividing/shortening unit divides or shortens at least one of the pair of line segments so that the drawing ranges of the pair of line segments do not overlap each other.