LASER BEAM MACHINING DEVICE WITH MIRROR TEMPERATURE CONTROL MECHANISM AND METHOD FOR CONTROLLING MIRROR TEMPERATURE OF LASER BEAM MACHINING DEVICE

PROBLEM TO BE SOLVED: To provide a laser beam machining device having a mirror temperature control mechanism which requires minimum water piping, causes no damage to such an optical part as a reflection mirror due to a water leak, eliminates complications around the device due to the water piping, and has improved workability of a maintenance job, and a method for controlling the mirror temperature of the laser beam machining device. SOLUTION: The device is characterized in that cooling mechanisms Kc and Kc' employing Peltier effect are provided on a reflection mirror Mr which reflects a laser beam Le, the cooling mechanisms uses a Peltier element Pe, the reflection mirror Mr is adhered to the lower temperature side of the element Pe, air cooling fins Fi for heat radiation are provided on the higher temperature side of the element Pe, or the air cooling fins Fi are provided and a cooling fan Fa is provided outside the fins in addition to the fins to enhance a cooling effect, thus a cooling function of the reflection mirror is promoted, and a condensation prevention function on the surface of the mirror is also provided.