Problem to be solved: to provide an elastic wave device capable of suppressing spurious by the mirror mode.Solution: the elastic wave device 1 is provided on the support substrate 2, the acoustic reflection film 7 provided on the support substrate 2, the piezoelectric layer 4 having the first principal surfaces 4A and 4B, and at least one of the first principal surface 4A and the second main surface 4b of the piezoelectric layer 4 and at least one of them The first plate electrode 5 and the second flat plate electrode 6 (excitation electrode) are provided.The acoustic reflective film 7 has an alternating acoustic impedance layer and a low acoustic impedance layer.At least one of the high acoustic impedance layer and the low acoustic impedance layer is a laminate of a first material layer 12a and a second material layer 12b, at least one of the longitudinal acoustic impedance and the transverse acoustic impedance is substantially the same.An interface 12C between the first material layer 12a and the second material layer 12b is provided with an uneven surface.Diagram
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