Provided is an ultrasonic imaging apparatus including: an inputter configured to receive an input of a region of interest (ROI) from a user; a beamformer configured to perform transmission/reception focusing with respect to a virtual source to be used for a synthetic aperture focusing method; a display; and a main controller configured to determine a position of the virtual source on the basis of an image quality in the received ROI and control the display to display the determined position of the virtual source.