A method of manufacturing surface acoustic wave device chips includes grinding a reverse side of a wafer with a surface acoustic wave device formed in each area demarcated by a plurality of crossing projected dicing lines on a face side of the wafer; before or after grinding, applying a laser beam to the reverse side of the wafer such that the laser beam is focused at a position within the wafer, the position being closer to the face side of the wafer than a position corresponding to a reverse side of each of the surface acoustic wave device chips to be produced from the wafer, thereby forming a modified layer for diffusing an acoustic wave; and after grinding and applying the laser beam, dividing the wafer along the projected dicing lines into a plurality of the surface acoustic wave device chips.