LASER MARKING DEVICE

PROBLEM TO BE SOLVED : To improve printing quality in a laser marking device in which a rare-earth doped optical fiber is used. SOLUTION : In the case where the laser output of a laser beam emitted from an optical fiber 19 is set to a set laser output P1, a driving current Iex1 and reaching time T1 corresponding to the set laser output P1 are read from a memory 13A. Then, in starting a marking operation, the maximum driving current IexM is supplied to high excitation semiconductor lasers 11B, 11C for the duration equivalent to the reaching time T1, and the driving current Iex1 is supplied after the lapse of T1. Further, in the case where the laser output of the laser beam emitted from the optical fiber 19 is set to P2, a driving current Iex2 and reaching time T2 corresponding to such output P2 are read from the memory 13A. Then, in starting a marking operation, the maximum driving current IexM is supplied to the high excitation semiconductor lasers 11B, 11C for the duration equivalent to the reaching time T2, and the driving current Iex2 is supplied after the lapse of T2.