DETERMINATION METHOD AND DETERMINATION DEVICE FOR LASER PROCESSING STATE

A determination method for determining a processing state includes detecting, using an optical sensor, at least one of heat radiation light, visible light, and reflected light generated at a welded portion formed at a surface of a workpiece by emission of a laser beam on the workpiece, obtaining, from the optical sensor, a signal indicating a change in one of heat radiation, visible light, and reflected light in a time section corresponding to a welding time of each workpiece, determining, as the processing state, the position and number of molten shape abnormality in a welded region having a molten length and a molten width by inputting a feature quantity to a determination model that determines the processing state, the feature quantity including signal intensity of the signal, the molten shape abnormality occurring when a foreign substance exists at an overlapping surface of the workpiece, and outputting a determination result.