PURPOSE: To reduce the resistance of a bus line electrode and to widen the pass band width by making the film thickness of the bus line electrode thicker than the film thickness of an IDT electrode and a reflector electrode.

CONSTITUTION: A resist 4 is coated on a substrate 1 whose surface is made flat, resist of parts 2, 3 corresponding to each electrode is exfoliated to form a metal with a film thickness required for a bus line electrode. Then a 2nd resist 7 is coated and the resist of an IDT and a reflector electrode 6 requiring a thin electrode is exfoliated. Then the electrode film of the electrode 6 is etched by using the 2nd resist as a mask to make the thickness thin up to the required film thickness. Then it is equivalent to increase the cross sectional area of the bus line electrode relatively and to decrease the resistance of the bus line. Thus, the increase in the resistance of the bus line is prevented and the pass band width is made wide.