Hysteresis characteristics, which are similar to those observed in ferroelectric crystals, are found in uniaxially stretched poly(vinylidene fluoride) under a high electric field above 300 kV/cm at room temperature. Various transducers such as stereophonic headphones, tweeters, microphones and phonograph cartridges have been developed with polarized poly(vinylidene fluoride) films. These transducers have quite simple structures because the diaphragms are piezoelectric films and involve transducing function in themselves.