ELASTIC WAVE DEVICE AND METHOD FOR MANUFACTURING SAME

Provided is an elastic wave device that is high sonic-speed, is able to suppress the effects of spurious response from modes other than the mode being used, and uses plate waves. An elastic wave device (1) comprising: a supporting layer (2) in which through-hole or a concave part (2a) opening in a top surface is formed; a piezoelectric thin film (4) formed on the supporting layer (2) so as to extend over the concave part (2a) or the through-hole of the supporting layer (2); and an IDT electrode (5) formed on at least one of a top surface and a bottom surface of the piezoelectric thin film (4) in a region of the piezoelectric thin film (4) that extends over the concave part (2a) or the through-hole; the elastic wave gear device using a secondary mode of plate waves having a U1 component as the primary component, the piezoelectric thin film (4) being composed of LiTaO₃, and each Euler angle (φ, θ, ψ) of the LiTaO₃ being within the range of regions (R1 to R7) enclosed by solid lines in FIGS. 4 to 10.