Provided is a stretching method of an organic piezoelectric material which sequentially performs a primary stretching step for carrying out primary stretching of an organic piezoelectric material which has not been stretched, a heat treatment step for heat treating the organic piezoelectric material subjected to primary stretching, and a cooling step for carrying out secondary stretching of the heat treated organic piezoelectric material while the organic piezoelectric material is cooled down to the room temperature, and is characterized in that tension is applied continuously to the organic piezoelectric material from the primary stretching step to the cooling step without releasing the tension, and heat treatment is carried out while keeping the tension in a range of 0.1-500 kPa. A stretching method and a production method for producing an organic piezoelectric material exhibiting excellent planarity, machining characteristics and piezoelectric characteristics and suitable for high frequency and broadband are thereby provided, and an ultrasound transducer using the organic piezoelectric material produced by the method, and an ultrasound medical image diagnosis device are also provided.
