Acoustic wave element and acoustic wave device using same

An acoustic wave element, comprising:

• a piezoelectric substrate;
• and
• an IDT electrode located on a top surface of the piezoelectric substrate;
• wherein the IDT electrode comprises
• a first bus bar and a second bus bar which face each other in a direction perpendicular to a propagation direction of an acoustic wave,
• a plurality of first electrode fingers which extend from the first bus bar toward the second bus bar and are aligned in the propagation direction,
• a plurality of second electrode fingers which extend from the second bus bar toward the first bus bar, are aligned in the propagation direction, and mutually intersect with the plurality of first electrode fingers,
• a plurality of first dummy electrodes which extend from the first bus bar toward the second bus bar, are aligned in the propagation direction, and comprise front ends which face front ends of the plurality of second electrode fingers with a gap,
• a plurality of second dummy electrodes which extend from the second bus bar toward the first bus bar, are aligned in the propagation direction, and comprise front ends which face front ends of the plurality of first electrode fingers with a gap,
• a plurality of first auxiliary electrodes which protrude toward sides from front end side portions of the plurality of first dummy electrodes, and
• a plurality of second auxiliary electrodes which protrude toward sides from front end side portions of the plurality of second dummy electrodes,
• at least part of the plurality of first auxiliary electrodes comprise edge portions located a side of the second bus bar, the edge portions being located closer to the side of the second bus bar the more to a side of the front end, and
• at least part of the plurality of second auxiliary electrodes comprise edge portions located a side of the first bus bar, the edge portions being located closer to a side of the first bus bar the more to a side of the front end.