PURPOSE: To heighten reliability by reducing the change of a center frequency due to change in the lapse of time when a surface acoustic wave element is operated by applying etching to a substrate surface and increasing surface roughness, and performing single crystal growth of aluminum.

CONSTITUTION: When the surface acoustic wave element in which lithium group oxide single crystal is set as a piezoelectric substrate and an electrode is formed on the substrate is manufactured, mirror working is applied to the surface of the substrate by grinding, and after that, the surface roughness is set at a value between 200 and 1500 nanometers in mean square roughness by applying etching, and the single crystal growth of metallic film is performed. Also, the etching by hydrofluoric acid or miscible liquid setting the hydrofluoric acid as a principal component is applied to the surface of the substrate. Furthermore, aluminum or aluminum alloy is used as the metallic film. The change of internal stress of aluminum film can be reduced, and the change of the frequency can be reduced while the surface acoustic wave element is being operated.