An acoustic wave device includes a piezoelectric body including first and second main surfaces facing each other, an IDT electrode provided on the first main surface of the piezoelectric body and including electrode fingers, a high acoustic velocity member on the second main surface side of the piezoelectric body, in which an acoustic velocity of a propagating bulk wave is higher than an acoustic velocity of an acoustic wave propagating through the piezoelectric body, and a first dielectric film provided on an upper surface of the electrode fingers, in which a portion where a dielectric is not present is provided between the electrode fingers of the IDT electrode.