A surface acoustic wave device has a large electromechanical coupling coefficient, a low insertion loss, and high resistance to static electricity. In the surface acoustic wave device, a piezoelectric substance includes a plurality of grooves. Each electrode finger of an IDT electrode includes a first electrode layer disposed in the grooves and a second electrode layer disposed on the first electrode layer and located at a position higher than the upper opening of the grooves. In a surface acoustic wave device, the one-half power of the product of the cube of the average density (ρa) of the first electrode layer and the average stiffness (C44a) of the first electrode layer [(ρa3×C44a)1/2] is larger than the one-half power of the product of the cube of the average density (ρb) of the second electrode layer and the average stiffness (C44b) of the second electrode layer [(ρb3×C44b)1/2].