unit 11 a transmission delay pattern storage unit 12 a transmission control unit 13 a drive signal generating unit 14 a reception signal processing unit 21 a reception delay pattern storage unit 22 a reception control unit 23 a b mode image generating unit 24 a complex signal calculating unit 25 a complex signal interpolating unit 26 an amplitude and phase calculating unit 27 an image signal generating unit 28 a d a converter 29 a display unit 30 a console 31 a control unit 32 and a storage unit 33 the ultrasonic probe 10 is used in contact with an object to be inspected and includes plural ultrasonic transducers 10 a forming a one dimensional or two dimensional transducer array these ultrasonic transducers 10 a transmit an ultrasonic beam based on applied drive signals and receive propagating ultrasonic echoes to output reception signals each ultrasonic transducer includes a vibrator having electrodes formed on both ends of a material having a piezoelectric property piezoelectric material such as a piezoelectric ceramic represented by pzt pb lead zirconate titanate a polymeric piezoelectric element represented by pvdf polyvinylidene difluoride or the like when a pulse or continuous wave voltage is applied to the electrodes of the vibrator the piezoelectric material expands and contracts by the expansion and contraction pulse or continuous wave ultrasonic waves are generated from the respective vibrators and an ultrasonic beam is formed by synthesizing these ultrasonic waves further the respective vibrators expand and contract by receiving the propagating ultrasonic waves to generate electric signals these electric signals are outputted as reception signals of ultrasonic waves the scan control unit 11 sequentially sets the transmission direction of an ultrasonic beam and the.