Acoustic wave device

An acoustic wave device comprising:

• a piezoelectric substrate including a piezoelectric layer;
• and
• an IDT electrode provided on the piezoelectric layer, and including a plurality of first electrode fingers and a plurality of second electrode fingers that are interdigitated with each other and coupled to mutually different potentials;
• wherein
• a portion of the piezoelectric layer where the IDT electrode is provided includes an intersection region, and when a direction in which the plurality of first electrode fingers and the plurality of second electrode fingers extend is defined as an electrode finger extending direction, a direction orthogonal to the electrode finger extending direction is defined as an electrode finger orthogonal direction, and the IDT electrode is viewed in the electrode finger orthogonal direction, a region where the first electrode finger and the second electrode finger, which are adjacent to each other, overlap each other is the intersection region;
• the piezoelectric layer includes a first region and a second region having a polarization direction different from that of the first region, and the first region and the second region are positioned at least in the intersection region;
• the intersection region includes a polarization change region where the first region and the second region are alternately arranged in the electrode finger orthogonal direction;
• in plan view, the first region positioned in the polarization change region overlaps at least the first electrode finger of the first electrode finger and the second electrode finger, and the first region overlaps at least a portion of the first electrode finger;
• in plan view, the second region positioned in the polarization change region overlaps at least a portion of the second electrode finger;
• and
• when a region between centers of one pair of the first electrode finger and the second electrode finger in the electrode finger orthogonal direction is defined as one section, in the polarization change region, the sections in which both of the first region and the second region are positioned are provided periodically.