A surface acoustic wave device including a substrate and an electrode structure formed on the substrate, said substrate being made of a doubly rotated Y-cut (&agr;X-&thgr;Y cut) Langasite (La3Ga5SiO14), a rotation angle &agr; from the X axis being substantially 50°±5° and a rotation angle &thgr; from the Y axis being substantially 19°-30°. The device further includes a normal type electrode structure which reveals a natural single-phase unidirectional transducer property together with an anisotropy of the substrate. The device further has a double electrode type electrode structure which cancels the directionality, or a floating type electrode structure which reverses the directionality. The electrode structure is formed to constitute a surface acoustic wave filter having a low insertion loss and an excellent phase property.