The present invention relates to a laser processing method, a controller, and a robot system. The quality of the machining can be maintained even when the properties of the workpiece change. The laserprocessing method uses a head and a robot, and the head can change the shape of the irradiation trajectory of the laser irradiation, and the robot moves the head. Further, the laser processing methodincludes an acquisition step, a division step, and an adjustment step. The acquisition process acquires attribute information indicating a distribution of attributes in a processed area of the workpiece. The dividing process divides the shape of the irradiation trajectory into a plurality of divided regions. The adjustment step adjusts at least one of the trajectory speed and the output of the head-based laser light for each divided region based on the attribute information.