An ultrasonic sensor and a display device and may drive a plurality of sensing pixels disposed in the ultrasonic sensor simultaneously to transmit an ultrasonic wave, may make a first electrode disposed in a sensing pixel to be floated at a timing receiving a reflected signal to store the signal, and then may perform a sensing sequentially. Therefore, as an accurate sensing may be possible while reducing a duration and a number of an ultrasonic wave transmitting, a sensitivity and an accuracy of a sensing may be maintained while improving a driving efficiency of the ultrasonic sensor.