Abstract: Ultrasound imaging apparatus for transmitting ultrasonic signals to a subject to be diagnosed and for reconstructing an ultrasonic diagnostic image from received ultrasonic echo signals, the ultrasound imaging apparatus including: (a) a plurality of transducer elements which are two-dimensionally oriented in an array having a lateral direction and an elevation direction, the transducer elements converting electrical driving signals supplied thereto into the ultrasonic transmitting signals and converting the ultrasonic echo signals into electrical echo signals; (b) apparatus for generating and supplying the electrical driving signals to the transducer elements; (c) apparatus for selectively combining the electrical driving signals and the electrical echo signals sent to or received from transducer elements in the elevation direction; and (d) apparatus for converting the selectively combined electrical echo signals into the ultrasound diagnostic image.