Acoustic wave filter

An acoustic wave filter comprising:

• a piezoelectric substrate including a first major surface and a second major surface that are opposite to each other;
• a functional electrode and a first wiring portion that are located at a first major surface of the piezoelectric substrate, the first wiring portion being connected to the functional electrode;
• a mounting substrate including a third major surface and a fourth major surface that are opposite to each other;
• and
• a second wiring portion located at the third major surface of the mounting substrate, the second wiring portion being connected to ground;
• wherein
• the first major surface of the piezoelectric substrate, and the third major surface of the mounting substrate are opposite to each other;
• and
• an inter-wiring distance is less than a wiring width of the first wiring portion, the inter-wiring distance being a distance between the first wiring portion and a portion of the second wiring portion that overlaps the first wiring portion in plan view seen in a direction of thickness of the mounting substrate.