To be able to control an aperture in ultrasound transducer units comprised such that the signals from a plurality of ultrasound transducers are added and output. An ultrasound probe comprising a plurality of ultrasound transducers, a plurality of delay circuits, and an adder circuit, and configured to be able to control a reception aperture of ultrasound waves. The delay circuit performs a delay processing to reception signals. The adder circuit adds and outputs the reception signals for each predetermined group. The ultrasound probe further comprises a gate means. The gate means switches connection and disconnection of the signal path for each signal path arranged between the ultrasound transducer and the adder circuit. The gate means also connects only the signal path from the ultrasound transducer corresponding to the initial reception aperture that is previously set after the transmission of ultrasound waves within the cycle of the ultrasound waves and sequentially connects the corresponding signal path from the ultrasound transducer that is closer to the initial reception aperture according to the lapse in time of the reception period.