To provide a laser processing method and a laser processing device capable of properly forming a periodic structure on a flat surface of a material.SOLUTION: A laser processing method comprises a flattening proces of forming a processing flat surface flattened by processing a projection part P of a processing object surface Wa by scanning while applying a pulse laser beam to the processing object surface Wa having irregularities. This flattening process forms the processing flat surface by processing the processing object surface Wa by a pulse laser beam (an energy ball E1) of removably adjusting a projection part P of the processing object surface Wa and formably adjusting a nano periodic structure based on the wave length of the pulse laser beam, in the final scanning of the pulse laser beam for forming the processing flat surface.SELECTED DRAWING: Figure 11
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