An ultrasound diagnostic apparatus comprising: an image memory configured to store ultrasound images of a plurality of frames; a urinary bladder extraction unit configured to extract a urinary bladder region from each of the ultrasound images of the plurality of frames; a feature quantity calculation unit configured to calculate a feature quantity related to the urinary bladder region extracted for each of the ultrasound images of the plurality of frames by the urinary bladder extraction unit; a candidate frame extraction unit configured to extract, from the ultrasound images of the plurality of frames, an ultrasound image of a frame for which the feature quantity calculated by the feature quantity calculation unit becomes a local maximum, as an ultrasound image of at least one candidate frame that serves as a candidate subjected to measurement; a measurement frame selection unit configured to select an ultrasound image of a measurement frame that serves as a target subjected to measurement from the ultrasound image of the at least one candidate frame extracted by the candidate frame extraction unit; and a urine volume measurement unit configured to analyze the ultrasound image of the measurement frame selected by the measurement frame selection unit to measure a urine volume; characterized in that in a case where a difference between a local maximum value of the feature quantity in the ultrasound image of the frame for which the feature quantity calculated by the feature quantity calculation unit becomes the local maximum and a local minimum value of the feature quantity adjacent to the local maximum value in time series is smaller than a predetermined difference threshold, the candidate frame extraction unit is configured to remove the ultrasound image of the frame for which the feature quantity becomes the local maximum from the ultrasound image of the at least one candidate frame. an image memory configured to store ultrasound images of a plurality of frames; a urinary bladder extraction unit configured to extract a urinary bladder region from each of the ultrasound images of the plurality of frames; a feature quantity calculation unit configured to calculate a feature quantity related to the urinary bladder region extracted for each of the ultrasound images of the plurality of frames by the urinary bladder extraction unit; a candidate frame extraction unit configured to extract, from the ultrasound images of the plurality of frames, an ultrasound image of a frame for which the feature quantity calculated by the feature quantity calculation unit becomes a local maximum, as an ultrasound image of at least one candidate frame that serves as a candidate subjected to measurement; a measurement frame selection unit configured to select an ultrasound image of a measurement frame that serves as a target subjected to measurement from the ultrasound image of the at least one candidate frame extracted by the candidate frame extraction unit; and a urine volume measurement unit configured to analyze the ultrasound image of the measurement frame selected by the measurement frame selection unit to measure a urine volume; characterized in that in a case where a difference between a local maximum value of the feature quantity in the ultrasound image of the frame for which the feature quantity calculated by the feature quantity calculation unit becomes the local maximum and a local minimum value of the feature quantity adjacent to the local maximum value in time series is smaller than a predetermined difference threshold, the candidate frame extraction unit is configured to remove the ultrasound image of the frame for which the feature quantity becomes the local maximum from the ultrasound image of the at least one candidate frame. <EOS>