An ultrasonic device includes an element substrate provided with an ultrasonic transducer array having a plurality of ultrasonic transducers arranged in an array, and having a first surface and a second surface located on an opposite side to the first surface, a terminal part disposed on the first surface of the element substrate, and outside the ultrasonic transducer array in a planar view viewed from a normal direction of the first surface, and electrically connected to the ultrasonic transducers, and a reinforcing plate disposed on the second surface of the element substrate in an area overlapping the terminal part in the planar view, and higher in bending rigidity than the element substrate.
