Reference image display method and ultrasonic diagnostic apparatus in the ultrasonic diagnostic

An ultrasonic image 105, 106 captured by the ultrasonic probe 104, a tomographic image corresponding to the scan plane of the ultrasonic image from the volume image data of the volume data storage unit 107 which is captured in advance by the image diagnostic apparatus 102 in case of displaying the extracted and reference image 111 comprising the same screen 114, by extracting the portion corresponding to the viewing area of ​​the ultrasonic image of the reference image, sector reference image of the same region and the ultrasound image by displaying an image, and / or by displaying the ultrasonic image and the same magnification, so that the correspondence between the two images can be easily grasped. Further, by displaying lower the brightness of a portion out of the view area of ​​the ultrasonic image of the reference image, to allow comparative observation without losing information of the reference image.