PURPOSE: To establish small size, thin type and low cost, by forming the plane and side electrode with the photolithography techonlogy.

CONSTITUTION: The +5° x cut crystal substrate 11 is polished for the both sides by 50 to 200μ thick, coating is made for the both sides for the metal thin film 12 in common use for the fluorine proof mask and the flat electrode in processing of etching in diapason shape, the plane electrode patern 13 is formed for the both sides by using the negative type photo resist, patterning of the diapason 14 is made by using the positive type photo resist, etching is made for the thin film 12 and the substrate 11, side electrode film 15 is formed, the photo resist 14 for the thin film 15 formed on the plane part and the photo resist 14 at background are removed, the thin film 12 is etched by taking the negatibe type photo resist 13 as a mask, and the resist 13 is stripped. Further, the crystal plate is cut by revolving the X plate around the X axis by 0 to 10° and around Y' axis by 70 to 90°