Acoustic wave device and method of producing the same

A method of producing an acoustic wave device, comprising:

• forming an interdigital electrode having a plurality of electrode fingers on a piezoelectric substrate;
• forming a barrier film so as to cover the interdigital electrode;
• forming a medium on the barrier film;
• measuring a frequency characteristic of an acoustic wave excited by the interdigital electrode;
• and
• forming, in an excitation region where the acoustic wave is excited by the interdigital electrode, an adjustment region having a different thickness from other portions by patterning the barrier layer or further providing an adjustment film,
• wherein when forming the adjustment region, an area T of the adjustment region in the excitation region is adjusted in accordance with the measured frequency characteristic.