Abstract: An ultrasonic sensor installable to a vehicle includes a shield section, a vibration conversion section, and an electric circuit section. The shield section includes a conductive layer. The conductive layer is bonded to an outer plate, which is a body part formed of non-conductive material, on an inner surface side of the outer plate. A vibration conversion section, which has a function of converting ultrasonic vibration and electrical signals, is bonded to the shield section to enable ultrasonic vibration together with the outer plate. An electric circuit section is electrically connected to the vibration conversion section to enable the transfer of the electric signals to and from the vibration conversion section. The shield section is electrically short-circuited to a ground side line electrically connected to the electric circuit section to shield the vibration conversion section.

Abstract: An ultrasonic transducer includes a transducer case and an ultrasonic element. The transducer case is formed into a bottomed, cylindrical shape having a side plate portion and a bottom plate portion that seals one end side of the side plate portion in an axial direction to configure a diaphragm. The ultrasonic element is fixedly supported to the bottom plate portion to face an interior space surrounded by the side plate portion and the bottom plate portion. The ultrasonic element is arranged in a position being offset in an in-plane direction orthogonal to the axial direction relative to a center position of the diaphragm in the in-plane direction to be capable of generating a first transmission wave having first directivity characteristics and a second transmission wave having second directivity characteristics that are directivity characteristics differing from the first directivity characteristics and in which sound pressure in the axial direction is decreased.