A method and an apparatus for performing a beamforming by using unfocused ultrasounds are disclosed. Some embodiments of the present disclosure provide a method and an apparatus for performing a beamforming, when processing an ultrasound image obtained by transmitting unfocused ultrasounds to a field-of-view and receiving reflection signals from the field-of-view, which include calculating transmission delay times taken by ultrasounds transmitted by transmit elements of a transducer to arrive at a receive focusing point, calculating reception delay times taken by reflection ultrasound signals reflected at the receive focusing point to arrive at receive elements of the transducer, and applying the calculations of the transmission delay times and the reception delay times to reception signals at the receive elements.
