According to a 2-dimensional map having longitudinal and horizontal axes indicating different elastic information, hue or luminance of each pixel is mapped correspondingly to their elastic information, and the elastic information is combined to construct one elastic image. With this, a plurality of items of elastic information can be combined into one elastic image and displayed, and thereby the elastic image can be scanned in real time while observing it. Even where one item of elastic information may be in a gray zone, i.e., benign or malignant, another item of information may definitely show the differentiation between benign or malignant, and therefore highly accurate differentiation is possible. In addition, the user can perform diagnosis with the elastic image into which the plurality of items of elastic information is combined without moving the line of sight, thereby obtaining an improved visibility.