An elastic wave device includes IDT electrodes on a first main surface of a piezoelectric substrate and a heat dissipating film on a second main surface and including a pair of opposing main surfaces and side surfaces connecting the pair of main surfaces. At least a portion of the side surfaces of the heat dissipating film is located in an inner side portion relative to the outer circumference of the second main surface of the piezoelectric substrate on an arbitrary cross section along a direction connecting the pair of main surfaces of the heat dissipating film.