A SAW device manufacturing method includes a piezoelectric ceramic substrate polishing step of polishing a first surface of the piezoelectric ceramic substrate, a support substrate polishing step of polishing a first surface of the support substrate, a bonding step of bonding the first surface of the piezoelectric ceramic substrate to the first surface of the support substrate to thereby form a stacked substrate, a grinding step of grinding a second surface of the piezoelectric ceramic substrate, and a vibration diffusion layer forming step of applying a laser beam to the stacked substrate in the condition where the focal point of the laser beam is positioned inside the piezoelectric ceramic substrate to thereby form a modified layer as a vibration diffusion layer inside the piezoelectric ceramic substrate.