Acoustic wave device

An acoustic wave device comprising:

• a support with a thickness extending in a first direction;
• a piezoelectric layer extending in the first direction of the support;
• and
• an interdigital transducer electrode extending in the first direction of the piezoelectric layer and including a plurality of first electrode fingers extending in a second direction orthogonal to the first direction, a first busbar electrode connected to the plurality of first electrode fingers, a plurality of second electrode fingers extending in the second direction and facing corresponding ones of the plurality of first electrode fingers in a third direction orthogonal to the second direction, and a second busbar electrode connect to the plurality of second electrode fingers;
• wherein
• the support includes a hollow on a side thereof adjacent to the piezoelectric layer and at least partially overlapping the interdigital transducer electrode in plan view in the first direction;
• the piezoelectric layer includes at least one first through hole penetrating the piezoelectric layer in a region between at least one first electrode finger and the second busbar electrode in plan view in the first direction;
• and
• the first through hole communicates with the hollow, has a length in the third direction, and overlaps a portion of at least one second electrode finger in plan view in the first direction.