An acoustic wave device that has a better TCF and can improve a resonator Q or impedance ratio is provided. The acoustic wave device includes a substrate 11 containing 70 mass % or greater of silicon dioxide (SiO2), a piezoelectric thin film 12 including LiTaO3 crystal or LiNbO3 crystal and disposed on the substrate 11, and an interdigital transducer electrode 13 disposed in contact with the piezoelectric thin film 12.