The present disclosure relates to ultrasonic sensors, ultrasonic sensing devices and display devices. The ultrasonic sensor includes an array of thin film transistors in which first electrodes are disposed, a piezoelectric material, and second electrodes. In order to generate ultrasonic waves and perform sensing, the second electrode is disposed in a patterned structure in which the second electrode is divided into multiple second electrodes, and a high voltage in the form of pulse is applied to the second electrode. Thus, in accordance with embodiments of the present disclosure, a high voltage is not applied to the array of thin film transistors; therefore, it is possible to reduce or overcome degradation of circuit elements disposed in the array of thin film transistors. Accordingly, it is possible to improve the reliability and lifetime of the circuit elements disposed in the array of thin film transistors, while performing sensing.