An ultrasonic transducer element includes a polymer piezoelectric film having a plurality of sections. The sections are defined by wave planes of ultrasonic waves having substantially .lambda./2 phase difference emanated from an imaginary focal point or line located in front of the piezoelectric film. .lambda. is the wave length of the ultrasonic waves within an acoustic transmission medium located between the piezoelectric film and the imaginary focal point or line. The sections are arranged so that ultrasonic waves emanated from adjacent sections have substantially no phase difference at the imaginary focal point or line. Front and rear electrodes are deposited on opposite surfaces of the piezoelectric film.