An ultrasonic device that transmits and receives ultrasonic waves includes: ultrasonic elements having first and second surfaces from which the ultrasonic waves are emitted; and a backing unit that supports the second surfaces of the ultrasonic elements and attenuates the ultrasonic waves emitted to the second surface side. The backing unit includes microlenses, which are arranged on the second surface side of the ultrasonic elements so as to be located corresponding to the ultrasonic elements, and a backing member having slits through which the ultrasonic waves transmitted through the microlenses pass. The ultrasonic elements are arranged in the shape of an array, and the microlenses are arranged in the shape of an array corresponding to the ultrasonic elements.