A method of producing an acoustic wave device includes: forming an interdigital electrode 3 on a piezoelectric substrate 2; forming a barrier film 4 so as to cover the interdigital electrode 3; forming a medium 5 on the barrier film 4; measuring a frequency characteristic of an acoustic wave excited by the interdigital electrode 3; and forming, in an excitation region, an adjustment region having a thickness different from other portions by patterning the barrier film 4 or further providing an adjustment film. When forming the adjustment region, an area T of the adjusting area is adjusted in accordance with the measured frequency characteristic.