Elastic wave device

Provided is an elastic wave device capable of suppressing variations in the thickness of a piezoelectric layer. An elastic wave device (10) is provided with: a support member (13) having a support substrate; a piezoelectric layer (14) provided on the support member (13); and an excitation electrode provided on the piezoelectric layer (14). The support member (13) is provided with a cavity (13c). In a plan view, at least a portion of the excitation electrode overlaps the hollow portion (13c). A portion of the piezoelectric layer (14) that overlaps the hollow portion (13c) in plan view is a thin film portion (15). The film portion (15) has a first direction (w1) and a second direction (w2) orthogonal to the first direction (w1). The film portion (15) has a central portion (15c) located at the center in the first direction (w1), and a first portion (15a) and a second portion (15b) facing each other across the central portion (15c) in the first direction (w1), and has an outer peripheral edge. At least a portion