An ultrasonic wave sensor includes an oscillating plate including a plurality of oscillators, a wall portion provided on the oscillating plate and surrounding the oscillator, a first piezoelectric element provided in the predetermined number of oscillators among the plurality of oscillators, and a second piezoelectric element provided in the oscillator where the first piezoelectric element is not provided. An input and an output of a drive signal are possible to the first piezoelectric element, and the first piezoelectric element is connected to at least another first piezoelectric element in parallel. The second piezoelectric element is electrically insulated from the first piezoelectric element. The second piezoelectric element is disposed between the first piezoelectric elements adjacent in one direction.