An acoustic wave device includes: a first substrate made of a piezoelectric material; an acoustic wave element located on the first substrate; a bump located on the first substrate; a second substrate located on the first substrate through the bump, the second substrate facing the first substrate across an air gap; and a support layer that is located in at least a part of a periphery of the first substrate, is in contact with a side surface of the first substrate, and has a less linear thermal expansion coefficient than the first substrate.