1. A method of analyzing elastography of tissue using a one-dimensional (1D) ultrasound probe, the method comprising: acquiring two-dimensional (2D) ultrasound images with respect to a region of interest (ROI), of an object to be diagnosed, in which a shear wave is induced using the 1D ultrasound probe; measuring a displacement of the shear wave from the acquired 2D ultrasound images; estimating a change rate in the displacement of the shear wave along a y-axis direction orthogonal to a 2D plane in which the acquired 2D ultrasound images are shown, using the measured displacement; and analyzing elastography information of tissue in the ROI using the measured displacement and the estimated displacement change rate.