An ultrasound diagnostic apparatus (1, 1A, 1B, 1C, 1D) that displays a blood vessel of a subject and an insert inserted into the blood vessel in an ultrasound image, the ultrasound diagnostic apparatus comprising: a transducer array; an image acquisition unit that causes the transducer array to transmit an ultrasound beam toward the subject and receives an ultrasound echo generated inside the subject to acquire the ultrasound image; a display device that displays the ultrasound image acquired by the image acquisition unit; an image analysis unit that analyzes the ultrasound image acquired by the image acquisition unit to detect the blood vessel and the insert in the ultrasound image; a highlighting unit that highlights the blood vessel detected by the image analysis unit in a case where the ultrasound image is displayed on the display device; and an apparatus controller that performs control such that the highlighting unit changes a form in highlighting the blood vessel depending on a relative positional relationship between the blood vessel and the insert detected by the image analysis unit, wherein the image analysis unit specifies a physical quantity representing the relative positional relationship between the detected blood vessel and the insert, the apparatus controller performs control such that, in a case where the physical quantity specified by the image analysis unit is greater than a threshold value, the highlighting unit highlights the blood vessel in a first form, and in a case where the physical quantity specified by the image analysis unit is smaller than the threshold value, the highlighting unit highlights the blood vessel in a second form different from the first form, wherein, in a case where the insert and a plurality of the blood vessels are detected, the image analysis unit specifies the physical quantity on each of the plurality of the blood vessels, the apparatus controller determines whether or not each of the plurality of the blood vessels detected by the image analysis unit is at a position reachable by the insert, and the apparatus controller performs control such that the highlighting unit highlights only the blood vessel that has the physical quantity specified by the image analysis unit smaller than the threshold value and is closest to the insert, among the blood vessels determined to be at the position reachable by the insert, in the second form. a transducer array; an image acquisition unit that causes the transducer array to transmit an ultrasound beam toward the subject and receives an ultrasound echo generated inside the subject to acquire the ultrasound image; a display device that displays the ultrasound image acquired by the image acquisition unit; an image analysis unit that analyzes the ultrasound image acquired by the image acquisition unit to detect the blood vessel and the insert in the ultrasound image; a highlighting unit that highlights the blood vessel detected by the image analysis unit in a case where the ultrasound image is displayed on the display device; and an apparatus controller that performs control such that the highlighting unit changes a form in highlighting the blood vessel depending on a relative positional relationship between the blood vessel and the insert detected by the image analysis unit, wherein the image analysis unit specifies a physical quantity representing the relative positional relationship between the detected blood vessel and the insert, the apparatus controller performs control such that, in a case where the physical quantity specified by the image analysis unit is greater than a threshold value, the highlighting unit highlights the blood vessel in a first form, and in a case where the physical quantity specified by the image analysis unit is smaller than the threshold value, the highlighting unit highlights the blood vessel in a second form different from the first form, wherein, in a case where the insert and a plurality of the blood vessels are detected, the image analysis unit specifies the physical quantity on each of the plurality of the blood vessels, the apparatus controller determines whether or not each of the plurality of the blood vessels detected by the image analysis unit is at a position reachable by the insert, and the apparatus controller performs control such that the highlighting unit highlights only the blood vessel that has the physical quantity specified by the image analysis unit smaller than the threshold value and is closest to the insert, among the blood vessels determined to be at the position reachable by the insert, in the second form.