An ultrasonic sensor and a display device is disclosed where a piezoelectric material disposed in each pixel area of the ultrasonic sensor is formed to have various thicknesses, or an electrode driving the piezoelectric material disposed in each pixel area has various areas, thereby providing the ultrasonic sensor that generates ultrasonic waves in various frequency bands. Accordingly, it can expand the frequency band of the ultrasonic waves generated by the ultrasonic sensor to improve its sensing performance, and obtain information of various frequency bands to provide the ultrasonic sensor capable of both the fingerprint sensing and the proximity sensing.