An ultrasonic vibrator driving apparatus performs driving by applying an alternating voltage as a drive voltage to an ultrasonic vibrator that includes a piezoelectric element and has a unique resonance frequency. The drive voltage is generated with a variable frequency in a frequency range including the resonance frequency of the ultrasonic vibrator. The frequency of the drive voltage is repeatedly swept with a predetermined sweep width and a predetermined sweep period so as to include the resonance frequency, based on a reference frequency set according to the resonance frequency of the ultrasonic vibrator. The sweep period and the sweep width are restricted by being associated so as to fall within a predetermined allowed range on a two-dimensional map divided by the sweep period and the sweep width.