An ultrasonograph is provided which, when a difference occurs between an expected tissue displacement direction and a displacement estimation direction, minimizes errors caused by the difference to improve accuracy of an elasticity image. The ultrasonograph comprises: an ultrasound probe to emit an ultrasound in a plurality of mutually crossing directions against a subject an ultrasound transmit and receive part to control the ultrasound probe to perform a plurality of transmissions and receptions of the ultrasound in each of the plurality of directions a displacement vector processor to calculate a displacement vector in each of the plurality of directions from a result of the plurality of transmissions and receptions of the ultrasound a strain processor to calculate strain information of the subject based on the displacement vectors an image data generator to create image data based on the calculated strain information and a display to display an image based on the image data.
