A method of displaying an elastic image, comprising: a) performing transmission/reception of an ultrasound signal along a plurality of scan lines set on a target object to obtain first ultrasound data, the target object including a plurality of tissues b) performing transmission/reception of an ultrasound signal along a plurality of scan lines set on the target object by applying a stress to the target object to obtain second ultrasound data c) calculating displacements of the tissues based on the first and second ultrasound data d) calculating strains in the tissues based on the calculated displacements e) forming an elastic image based on the calculated strains and a graph indicating changes of the tissues for the respective scan lines and f) displaying the elastic image together with the graph.
