To observe and measure changes with the lapse of time of an internal organ of a circulating organ system accompanying a pulsation such as the heart by a real time system.

A display space is formed in a virtual space conforming to a scanning shape by an ultrasonic beam which is peculiar for a probe of an ultrasonic image diagnosing device to be used (S11). By the ultrasonic image diagnosing device, a scanning is performed by a real time system in order, and data obtained by the scanning is fetched (S12). By an A/D(analogue/digital) converting means, the data is converted into a digital electric signal of a specified bit number (S13). The digital signal obtained under S13 is converted in such a manner that the brightness information is allotted into data of four arrays of three primary colors of RGB and an opacity α (S14). By allotting the data of the four arrays of the three primary colors of RGB and the opacity αobtained under the step S14 for the three-dimensional display space formed under the step S11, a three-dimensional image display is obtained (S15).