A dividing method for a workpiece having a substrate with a film formed on the front side thereof. A first laser beam is applied to the film from the front side of the workpiece along the streets formed on the film, thereby forming a plurality of laser processed grooves along the streets to cut the film along the streets. Thereafter, an adhesive tape is attached to the front side of the workpiece. Thereafter, a second laser beam is applied to the substrate from the back side of the workpiece along the streets in the condition where the focal point of the second laser beam is set inside the substrate, thereby forming a plurality of modified layers inside the substrate along the streets. Thereafter, the adhesive tape is expanded to thereby divide the substrate along the streets, thereby obtaining a plurality of individual devices. Thereafter, the back side of the substrate of each device is ground to remove the modified layers and reduce the thickness of each device to a predetermined thickness.