The number of signal lines connecting an ultrasonic probe (1) and an ultrasonic diagnostic apparatus main body (2) is reduced or wireless communication is realized by reducing a volume of data of reception signals outputted from plural ultrasonic transducers (10). The ultrasonic probe (1) includes: plural ultrasonic transducers (10) for transmitting ultrasonic waves according to drive signals and receiving ultrasonic echoes to output reception signals; signal processing units for performing orthogonal detection processing or orthogonal sampling processing on the reception signals to generate two signals representing a complex baseband signal; sampling units for sampling the two signals to generateparallel sample data; a serializing unit (30) for converting the parallel sample data into serial sample data; and a transmitting unit (50) for transmitting the serial sample data.