In an ultrasound diagnostic apparatus and an operation method of the ultrasound diagnostic apparatus of the invention, a control circuit performs polarization processing on a plurality of ultrasound transducers in a non-diagnosis period, during which transmission of ultrasound waves and reception of reflected waves for performing ultrasound diagnosis are not performed, in a case where the cumulative driving time of the plurality of ultrasound transducers for performing the ultrasound diagnosis becomes equal to or longer than a specified time. A transmission circuit generates a first transmission signal having a driving voltage for performing ultrasound diagnosis using a pulse generation circuit in the case of performing the ultrasound diagnosis, and generates a second transmission signal having a polarization voltage for performing polarization processing using the same pulse generation circuit as in the case of generating the first transmission signal in the case of performing the polarization processing.