Acoustic wave device and filter device

An acoustic wave device comprising:

• a piezoelectric substrate including a piezoelectric layer;
• and
• an IDT electrode on the piezoelectric layer;
• wherein
• the IDT electrode includes a first busbar and a second busbar facing each other, a plurality of first electrode fingers of which one end portion is connected to the first busbar, and a plurality of second electrode fingers of which one end portion is connected to the second busbar, and the plurality of first electrode fingers and the plurality of second electrode fingers are interdigitated with each other;
• shapes of the plurality of first electrode fingers and the plurality of second electrode fingers in a plan view include a shape of a circular arc or an elliptical arc;
• and
• when a virtual line formed by connecting tip ends of the plurality of second electrode fingers is defined as a first envelope, a virtual line formed by connecting tip ends of the plurality of first electrode fingers is defined as a second envelope, and a center of a circle including the circular arc or a midpoint of two focal points of an ellipse including the elliptical arc in the shapes of the first electrode fingers and the second electrode fingers is defined as a fixed point, a straight line connecting the fixed point and a tip end of a second electrode finger is not parallel to the first envelope, and a straight line connecting the fixed point and a tip end of a first electrode finger is not parallel to the second envelope.