Abstract: An object of the invention is to provide a SAW device where a device size is made smaller than that of a conventional structure, has a high Q value, and is excellent in a frequency temperature characteristic in a SAW device using a quartz substrate. Therefore, IDTs 2 including pluralities of electrode fingers mutually inserted and grating reflectors 3a and 3b positioned on both sides of the IDTs 2 are disposed on a piezoelectric substrate 1. The piezoelectric substrate 1 is a quartz flat plate where a cut angle ? of a rotation Y cut quartz substrate is set to satisfy a range of ?64.0°<?<?49.3° in a counterclockwise direction from a crystal Z-axis and a propagation direction of a surface acoustic wave is set to 90°±5° to a crystal X-axis, and a surface acoustic wave to be excited is an SH wave.

Abstract: An object of the invention is to provide a SAW device where a device size is made smaller than that of a conventional structure, has a high Q value, and is excellent in a frequency temperature characteristic in a SAW device using a quartz substrate. Therefore, IDTs 2 including pluralities of electrode fingers mutually inserted and grating reflectors 3a and 3b positioned on both sides of the IDTs 2 are disposed on a piezoelectric substrate 1. The piezoelectric substrate 1 is a quartz flat plate where a cut angle ? of a rotation Y cut quartz substrate is set to satisfy a range of ?64.0°<?<?49.3° in a counterclockwise direction from a crystal Z-axis and a propagation direction of a surface acoustic wave is set to 90°±5° to a crystal X-axis, and a surface acoustic wave to be excited is an SH wave.