Abstract: A SAW device includes a piezoelectric substrate and a package body holding the piezoelectric substrate, wherein the package body includes a bottom part carrying the piezoelectric substrate in a face-down state and a side wall part laterally surrounding the piezoelectric substrate, the bottom part carrying a wiring pattern for electrical connection with an electrode pattern on the piezoelectric substrate, the wiring pattern including a first ground pattern and a second ground pattern in a mutually separated relationship, the first ground pattern and the second ground pattern being connected electrically with each other.