In a laser beam processing method, when a laser beam is emitted along a second predetermined dividing line to form a second groove intersecting a first groove previously formed, the power output of the laser beam is allowed to be a first power output in a first interval, that is, until the second predetermined dividing line reaches a position immediately before the first groove. In a second interval from the position close to the first groove to the first groove reached by the second predetermined dividing line, the power output of the laser beam is set to a second power output lower than the first power output. Thus, overheat on the periphery of the second interval can be suppressed.