PROBLEM TO BE SOLVED: To provide an ultrasound oscillator driving device 60, which applies, via a conversion circuit 63, a sinusoidal alternating voltage Va as a drive voltage to an ultrasound oscillator 40 having an inherent resonance frequency, and which can suppress a leak current to the ground GND.SOLUTION: The ultrasound oscillator driving device comprises: a first current detection unit 65 which detects a first current i1 flowing from a drive voltage generating unit 62 to the conversion circuit 63； and a second current detection unit 66 which detects a second current i2 flowing from the conversion circuit 63 to the ultrasound oscillator 40. A frequency control unit 61 performs control to cause the drive voltage generating unit 62 to change the frequency of a rectangular-waveform alternating voltage Vg such that the difference between the first current i1 and the second current i2 approaches a minimum value.SELECTED DRAWING: Figure 1【課題】固有の共振周波数をもつ超音波振動子４０に対して変換回路６３を介して正弦波状の交番電圧Ｖａを駆動電圧として印加する超音波振動子駆動装置６０であって、接地ＧＮＤへのリーク電流を抑制できるものを提供すること。【解決手段】駆動電圧発生部６２から変換回路６３へ流れる第１の電流ｉ１を検出する第１の電流検出部６５と、変換回路６３から超音波振動子４０へ流れる第２の電流ｉ２を検出する第２の電流検出部６６とを備える。周波数制御部６１は、第１の電流ｉ１と第２の電流ｉ２との間の差が極小値に近づくように、駆動電圧発生部６２に対して矩形波状の交番電圧Ｖｇの周波数を変更させる制御を行う。【選択図】図１
