To adjust the frequency of a drive signal in response to the variation of a resonance frequency due to temperature or the like, while driving a piezoelectric blower through a driving signal of the resonance frequency.

A piezoelectric actuator 3 of the piezoelectric blower is driven through vibration control voltage Va. A detection voltage Vd generated through the displacement of the piezoelectric actuator 3 is supplied to a comparator 57 through an operational amplifier 56 to be compared with the vibration control voltage Va. A detection voltage SVd taken out in the output of the comparator 57 is converted into digital detection data Dd to be supplied to a CPU 51. The CPU 51 generates a vibration control voltage having a frequency equal to a frequency in which the detection voltage Vd becomes maximum by changing the frequency of the vibration control voltage Va.