A surface acoustic wave apparatus comprises a piezoelectric substrate 17 on the bottom face of which IDT electrodes 3 and 4 and an annular ground electrode 6 which encloses the IDT electrodes 3 and 4 and is connected to the IDT electrode 3, and a base substrate on the top face of which an annular ground conductor 7 is formed and which has an internal ground conductor layer 10a and a bottom face ground conductor layer 11a connected to the annular ground conductor 7 and an internal ground conductor layer 10b and a bottom face ground conductor layer 11b connected to the IDT electrode 4. A first ground conductor composed of the internal ground conductor layer 10a and the bottom face ground conductor layer 11a is electrically separated from a second ground conductor composed of the internal ground conductor layer 10b and the bottom face ground conductor layer 11b. The apparatus has an excellent out-of-band attenuation characteristic.