PURPOSE: To reduce the effect of a bulk wave generated at an input side electrode and reaching an output side electrode to deteriorate an out-band attenuation in the surface acoustic wave device used for a communication equipment or the like.
CONSTITUTION: The surface acoustic wave device is formed by fixing a piezoelectric substrate 1 on the front side of which an interdigital input side electrode 3 and an interdigital output electrode 4 are arranged to a stem 6 by using an adhesives 2, and the effective thickness being the sum of the thickness of the piezoelectric substrate 1 and the thickness of the adhesives 2 is selected to be a dimension at which a bulk wave generated in the input side electrode 3 does not give effect onto the out-band attenuation so as to reduce the effect of the bulk wave and to reduce the deterioration in the out-band attenuation.