Even when a region of interest (ROI) is changed on a frozen image, an elasticity image of ROI after the change can be displayed without executing re-measurement. An ultrasonic diagnostic apparatus 1 has a control unit 110 having a first ROI setting unit 38 and a second ROI setting unit 39. When ROI is set by the first ROI setting unit 38 of the control unit 110, an elasticity information calculating unit 32 sets an area larger than ROI as a calculation area, calculates distortion, elasticity modulus, etc. of a tissue corresponding to each measurement point on a tomographic image of the calculation area, generates elasticity information based on the distortion, the elasticity modulus, etc., and outputs the elasticity information to an elasticity information storing unit 33. The control unit 110 changes the position/size of ROI by the second ROI setting unit 39 under a state that the frozen image is displayed. The elasticity image constructing unit 34 reads the elasticity information corresponding to the changed ROI from the elasticity information storing unit 33, forms an elasticity image of the changed ROI and displays it on an image display unit 26.
