There is provided an ultrasound transducer device 2 including a plurality of piezoelectric single-crystal plates 44a to 44f that are stacked such that polarization components thereof are alternately inverted. The plurality of piezoelectric single-crystal plates 44a to 44f are stacked such that directions thereof in which strain deformation in a direction orthogonal to a direction of voltage application from electrodes 45a, 45b respectively interposed between the plurality of piezoelectric single-crystal plates becomes largest coincide with each other. There is also provided an ultrasound medical apparatus 1 including the ultrasound transducer device 2.