An ultrasound diagnostic apparatus comprising: an ultrasound probe; an image acquisition unit that acquires an ultrasound image of a subject by performing transmission and reception of an ultrasound beam to and from the ultrasound probe in accordance with a predetermined transmission/reception condition; a display unit that displays the ultrasound image acquired by the image acquisition unit; a bladder extraction unit that extracts a bladder based on the ultrasound image acquired by the image acquisition unit; and characterized by: means for determining whether a bladder has been extracted by the bladder extraction unit; a prostate extraction unit that extracts a prostate, responsive to a determination that the bladder has been extracted by the bladder extraction unit, based on the ultrasound image from which the bladder has been extracted by the bladder extraction unit; means for determining whether a prostate has been extracted by the prostate extraction unit; a region-of-interest setting unit that sets a region of interest at a depth position in the ultrasound image based on a position of the extracted prostate if it has been determined that the prostate has been extracted by the prostate extraction unit and that sets a region of interest at a depth position in the ultrasound image based on a position of the bladder extracted by the bladder extraction unit if it has been determined that the prostate has not been extracted by the prostate extraction unit; and an image quality adjustment unit that adjusts the transmission/reception condition according to the depth position of the region of interest set by the region-of-interest setting unit. an ultrasound probe; an image acquisition unit that acquires an ultrasound image of a subject by performing transmission and reception of an ultrasound beam to and from the ultrasound probe in accordance with a predetermined transmission/reception condition; a display unit that displays the ultrasound image acquired by the image acquisition unit; a bladder extraction unit that extracts a bladder based on the ultrasound image acquired by the image acquisition unit; and characterized by: means for determining whether a bladder has been extracted by the bladder extraction unit; a prostate extraction unit that extracts a prostate, responsive to a determination that the bladder has been extracted by the bladder extraction unit, based on the ultrasound image from which the bladder has been extracted by the bladder extraction unit; means for determining whether a prostate has been extracted by the prostate extraction unit; a region-of-interest setting unit that sets a region of interest at a depth position in the ultrasound image based on a position of the extracted prostate if it has been determined that the prostate has been extracted by the prostate extraction unit and that sets a region of interest at a depth position in the ultrasound image based on a position of the bladder extracted by the bladder extraction unit if it has been determined that the prostate has not been extracted by the prostate extraction unit; and an image quality adjustment unit that adjusts the transmission/reception condition according to the depth position of the region of interest set by the region-of-interest setting unit. means for determining whether a bladder has been extracted by the bladder extraction unit; a prostate extraction unit that extracts a prostate, responsive to a determination that the bladder has been extracted by the bladder extraction unit, based on the ultrasound image from which the bladder has been extracted by the bladder extraction unit; means for determining whether a prostate has been extracted by the prostate extraction unit; a region-of-interest setting unit that sets a region of interest at a depth position in the ultrasound image based on a position of the extracted prostate if it has been determined that the prostate has been extracted by the prostate extraction unit and that sets a region of interest at a depth position in the ultrasound image based on a position of the bladder extracted by the bladder extraction unit if it has been determined that the prostate has not been extracted by the prostate extraction unit; and an image quality adjustment unit that adjusts the transmission/reception condition according to the depth position of the region of interest set by the region-of-interest setting unit.