An ultrasonic sensor includes a case having a substantially cylindrical shape with a bottom. The case has a piezoelectric element provided on the bottom, and a cushion member is engaged with a side portion of an opening of the case. A substrate and pin terminals are engaged in and held by a holding portion of the cushion member. On the substrate, electrodes that are connected to the pin terminals are provided. An opening portion is provided in a top surface of the cushion member. Lead wires that are electrically connected to the piezoelectric element extend out from the opening portion and are connected to the electrodes. The inside of the case is filled with an elastic resin from the opening portion.