The invention is to realize a surface acoustic wave device that attains a wide band and a small size, and lowers a loss by utilizing the natural single-phase unidirectional transducer characteristics. The surface acoustic wave device comprises a piezoelectric substrate (1) and a pair of interdigitated electrodes (2) provided on one main surface of the piezoelectric substrate 1. As the material of the piezoelectric substrate (1), a single crystal is used that belongs to the point group 32, has the Ca3Ga2Ge4O14 type crystalline structure, comprises La, Ta, Ga and O as main components, and is represented by a chemical formula La3Ta0.5Ga5.5O14. When the cut angle of the substrate (1) and the propagation direction are represented by Eulerian angles (&phgr;, &thgr;, &psgr;), &phgr;, &thgr; and &psgr; are in a first region where &phgr; is from −5° to 5°, &thgr; is from 135° to 155°, and &psgr; is from 15° to 40°, or in a second region where &phgr; is from 10° to 20°, &thgr; is from 140° to 157°, and &psgr; is from 30° to 60°.