An ultrasound transducer according to the present invention includes: a plurality of piezoelectric elements configured to emit ultrasound according to input of an electric signal and convert ultrasound incident from an outside into an electric signal； and a mask portion that is 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 divided region； and allow the ultrasound to pass in the propagation direction in the divided regions except the masked divided region.
