A surface acoustic wave device includes a LiNbO3 substrate and is constructed such that a reflection coefficient of an IDT is not only high but the electromechanical coupling coefficient K2 is also high, and the range of Euler angles of the LiNbO3 substrate which obtains a wide range of the electromechanical coupling coefficient K2 is increased. A plurality of grooves are provided in the upper surface of the LiNbO3 substrate, and an IDT including a plurality of electrode fingers is provided and defined by a metal material filled in the plurality of grooves, and the metal material is made of Ag, Ni, or Cr or an alloy primarily including at least one Ag, Ni, or Cr.