1. A method of displaying stereoscopic information related to an ultrasound sectional plane of a target object, the method comprising: setting a line of interest on the ultrasound sectional plane of the target object based on a received input; obtaining an ultrasound signal of the ultrasound sectional plane of the target object along the set line of interest; converting the obtained ultrasound signal to represent the stereoscopic information in a three-dimensional manner; and displaying the stereoscopic information related to the ultrasound sectional plane of the target object.