Acoustic wave device and acoustic wave filter device

An acoustic wave device comprising:

• a piezoelectric layer including a first main surface and a second main surface facing the first main surface in a first direction;
• an IDT electrode provided on at least one of the first main surface or the second main surface of the piezoelectric layer and including a plurality of electrode fingers arranged in an arrangement direction;
• a support facing the second main surface of the piezoelectric layer and including an acoustic reflection portion on a side adjacent the second main surface of the piezoelectric layer;
• and
• a protective film provided on at least one of the first main surface or the second main surface of the piezoelectric layer;
• wherein
• in a region that overlaps, in plan view in the first direction, a first electrode finger, among the plurality of electrode fingers, that is located outermost in the arrangement direction, the protective film includes a surface of a first step where a side surface of the protective film is exposed in a direction intersecting a direction in which the first electrode finger extends;
• and
• d/p is about 0.5 or less, where d is a thickness of the piezoelectric layer and p is a center-to-center distance between adjacent electrode fingers.