An ultrasound image diagnostic apparatus U includes, a transmitter 12 to repeat alternating supply of first pulse signals and second pulse signals to the ultrasound probe 2, the second pulse signals being generated by polarity inversion of the first pulse signals； a receiver 13； a memory 14 to store first sound ray data corresponding to the first pulse signals； an adder 15 to add the stored first sound ray data and second sound ray data corresponding to the second pulse signals； a line-signal processor C to generate fundamental line data and harmonic line data； a needle emphasizing signal processor 23 to generate needle image data from the generated fundamental image data,； a harmonic signal processor 25 to generate harmonic image data； a synthesizer 27 to combine the needle image data and the harmonic image data； and a display controller 30 to display the synthesized image data.
