An elastic wave device includes elastic wave elements, each including a piezoelectric layer directly or indirectly supported by a supporting substrate and an electrode disposed in contact with the piezoelectric layer, and a highly heat-conductive member stacked on a surface of the supporting substrate, opposite to the surface supporting the piezoelectric layer, in which the thermal conductivity of the supporting substrate is higher than the thermal conductivity of the piezoelectric layer, the coefficient of linear expansion of the supporting substrate is lower than the coefficient of linear expansion of the piezoelectric layer, the highly heat-conductive member has a larger area than the surface of the supporting substrate supporting the piezoelectric layer, and the thermal conductivity of the highly heat-conductive member is higher than that of the piezoelectric layer.