Acoustic wave device

An acoustic wave device comprising:

• a support substrate;
• a piezoelectric film stacked directly on or indirectly above the support substrate;
• and
• an IDT electrode above the piezoelectric film;
• wherein
• the IDT electrode includes a first electrode finger and a second electrode finger which are interdigitated with each other;
• an intersecting region is provided in which the first electrode finger and the second electrode finger overlap with each other as viewed in an acoustic wave propagation direction;
• the intersecting region includes a central region at a center in a direction in which the first and second electrode fingers extend, and first and second edge regions on sides outside the central region in the direction in which the first and second electrode fingers extend, and acoustic velocities of acoustic waves in the first and second edge regions are lower than an acoustic velocity of an acoustic wave in the central region;
• a thickness Ht of the piezoelectric film in the central region is different from thicknesses He of the piezoelectric film in the first and second edge regions in the piezoelectric film;
• and
• at least either of the thickness Ht of the piezoelectric film in the central region and the thicknesses He of the piezoelectric film in the first and second edge regions is not more than about 1λ, where λ is a wavelength determined by an electrode finger pitch of the IDT electrode.