PURPOSE: To engrave a reference picture without using a template by intermittently controlling the output of a laser oscillator by the picture signal obtd. by scanning a reference picture by a sensor and relatively moving a laser head and work table corresponding to the scanning of the sensor.

CONSTITUTION: A picture sensor 11 scans on a reference picture 9 by a spot 10. A working control means 12 subjects a laser oscillator 14 to ON, OFF controlling by a picture signal 13. A laser light 3 is projected on a work 2 by being made a spot 5' by a laser head 4. A work table 1 is scanned in X direction by the breadth part of a reference video 9 and driven thereafter by displacing the scanning line in Y direction. Therefore, when the work table 1 is scanned in X direction the picture sensor 11 reads the variable density of the reference picture on a scanning line B. At this time, the laser head 4 is scanned along a scanning line C, projecting intermittently the spot 5' of the laser light corresponding to the variable density can be specified engraving is executed.