Provided is an ultrasound transducer for irradiating a subject with ultrasound and receiving an ultrasound echo reflected from the subject. The ultrasound transducer includes a plurality of piezoelectric elements configured to emit ultrasound according to input of an electric signal and convert ultrasound incident from outside into an electric signal, and a mask portion provided between the plurality of piezoelectric elements and a radiation surface of the ultrasound on the ultrasound transducer. The mask portion is configured to: mask any divided region among a plurality of divided regions obtained by dividing an elevation direction orthogonal to a plane parallel to a scanning direction of the ultrasound； reflect the ultrasound in a direction different from a propagation direction of the ultrasound on the masked division region； and allow the ultrasound to pass in the propagation direction in the plurality of divided regions except the masked divided region.
